12th international conference on colloid and surface chemistry

12th International Conference on Colloid and Surface Chemistry

May 16 – 18, 2016

“Petru Poni” Institute of Macromolecular Chemistry

Iasi, Romania

BOOK OF ABSTRACTS

CONTENTS

ORGANIZERS ................................................................................................................................................. 2

PREFACE ....................................................................................................................................................... 3

CONFERENCE TOPICS ................................................................................................................................... 4

SCIENTIFIC COMMITTEE ............................................................................................................................... 5

ORGANIZING COMMITTEE ............................................................................................................................ 6

SCIENTIFIC PROGRAM .................................................................................................................................. 7

PLENARY LECTURES ..................................................................................................................................... 9

KEYNOTE LECTURES ................................................................................................................................. 23

ORAL COMMUNICATIONS .......................................................................................................................... 27

POSTER PRESENTATIONS ......................................................................................................................... 51

SPONSORS .................................................................................................................................................. 75

AUTHOR’S INDEX ...................................................................................................................................... 86

2 12th International Conference on Colloid and Surface Chemistry, ICCSC’2016

ORGANIZERS

“Petru Poni” Institute of Macromolecular Chemistry, Iasi, Romania

“Ilie Murgulescu” Institute of Physical Chemistry, Bucharest, Romania

Romanian Chemical Society

SupraChem Lab – Laboratory of Supramolecular Chemistry for Adaptive Delivery

Systems ERA Chair initiative

Horizon 2020 WIDESPREAD 2-2014: ERA Chairs Project no 667387

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PREFACE

The Conference on Colloid and Surface Chemistry started 33 years ago in

Bucharest. During the years, the conference was hosted by Cluj-Napoca,

Timisoara and Galați. In 2013, the conference was hosted for the first time by

„Petru Poni” Institute of Macromolecular Chemistry, Iasi, an institute of

excellence of the Romanian Academy.

This year, the 12th International Conference on Colloid and Surface

Chemistry, ICCSC’2016 is organized once again by „Petru Poni” Institute of

Macromolecular Chemistry, in the period 16-18 May.

The conference offers the opportunity to present the newest scientific

achievements, encouraging a productive exchange of ideas and opinions. Active

participation from academy and industry is encouraged. We hope that the

conference will be the starting point for new and fruitful collaborations.

Waiting to welcome for the conference and, perhaps, a few days before or after

it,

Bogdan C. SIMIONESCU Dan Florin ANGHEL Co-presidents of ICCSC’2016


CONFERENCE TOPICS

1. Colloid and interface phenomena

2. Organic-inorganic hybrid materials

3. Sol-gel materials

4. Functionally modified surfaces

5. Micro- and nanostructured materials

6. Biomaterials and bioinspired materials

7. Green and environmental chemistry

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SCIENTIFIC COMMITTEE Acad. Bogdan C. SIMIONESCU, “Petru Poni” Institute of Macromolecular Chemistry,

Iasi, and “Gheorghe Asachi” Technical University of Iasi, Romania

Acad. Maria ZAHARESCU, “Ilie Murgulescu“ Institute of Physical Chemistry,

Bucharest, Romania

Dr. Georgeta POPESCU, founding member of the conference, Research Center for

Macromolecular and Membrane Materials, Bucuresti

Dr. Dan-Florin ANGHEL “Ilie Murgulescu“ Institute of Physical Chemistry, Bucharest,

Romania

Prof. Teresa BASINSKA, Center of Molecular and Macromolecular Studies, Polish

Academy of Sciences, Łódź, Poland

Dr. Oana CARP, “Ilie Murgulescu“ Institute of Physical Chemistry, Bucharest,

Romania

Dr. Dan DONESCU, The National Institute for Research & Development in Chemistry

and Petrochemistry, Bucharest, Romania

Dr. Ecaterina Stela DRĂGAN, “Petru Poni” Institute of Macromolecular Chemistry,

Iasi, Romania

Dr. Valeria HARABAGIU, “Petru Poni” Institute of Macromolecular Chemistry, Iasi,

Romania

Prof. Bjorn LINDMAN, Center of Chemistry and Chemical Engineering, Lund

University, Lund, Sweden

Prof. Constanța IBĂNESCU, “Gheorghe Asachi” Technical University of Iasi, Romania

Dr. Luminita MARIN, “Petru Poni” Institute of Macromolecular Chemistry, Iasi,

Romania

Prof. Maria MIGUEL, Department of Chemistry, Coimbra University, Coimbra,

Portugal

Dr. Marcela MIHAI, “Petru Poni” Institute of Macromolecular Chemistry, Iasi,

Romania

Dr. Mariana PINTEALĂ, “Petru Poni” Institute of Macromolecular Chemistry, Iasi,

Romania

Dr. Stergios PISPAS, Theoretical and Physical Chemistry Institute, National Hellenic

Research Foundation, Athens, Greece

Dr. Vlad Tudor POPA, “Ilie Murgulescu“ Institute of Physical Chemistry, Bucharest,

Romania

Prof. Stanislaw SLOMKOWSKI, Centre of Molecular and Macromolecular Studies,

Polish Academy of Sciences, Łódź, Poland


ORGANIZING COMMITTEE

Program Chair

Dr. Marcela MIHAI, “Petru Poni” Institute of Macromolecular Chemistry, Iasi, Romania

Members

Dr. Adriana BARAN, “Ilie Murgulescu“ Institute of Physical Chemistry, Bucharest, Romania

Dr. Ana Irina COCÂRŢĂ, “Petru Poni” Institute of Macromolecular Chemistry, Iasi, Romania

Dr. Florica DOROFTEI, “Petru Poni” Institute of Macromolecular Chemistry, Iasi, Romania

Dr. Claudiu Augustin GHIORGHIŢĂ, “Petru Poni” Institute of Macromolecular Chemistry, Iasi, Romania

Dr. Narcisa MARANGOCI, “Petru Poni” Institute of Macromolecular Chemistry, Iasi, Romania

Dr. Monica MAXIM, “Ilie Murgulescu“ Institute of Physical Chemistry, Bucharest, Romania

Dr. Radu Dan RUSU, “Petru Poni” Institute of Macromolecular Chemistry, Iasi, Romania

Dr. Gabriela STÎNGĂ, “Ilie Murgulescu“ Institute of Physical Chemistry, Bucharest, Romania

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SCIENTIFIC PROGRAM

Monday, May 16

800 – 915 Registration of Participants 0915 – 0930 Conference Opening

Session 1. CONFERENCES Conference hall

Chair: Bogdan C. SIMIONESCU, Dan-Florin ANGHEL 0930 – 1010 PL1. Björn LINDMAN, Lund University, Sweden 1010 – 1050 PL2. Maria ZAHARESCU, IMIPC, Bucharest, Romania 1050 – 1110 Coffee Break


Chair: Maria ZAHARESCU, Stanislaw SLOMKOWSKI 1110 – 1150 PL3. Simona SCHWARZ, IPF, Dresden, Germany 1150 – 1230 PL4. Stergios PISPAS, TPCI, Athens, Greece 1230 – 1330 ICMPP visit 1330 – 1500 Lunch


Chair: Svetlana BRATSKAYA, Valeria HARABAGIU 1500 – 1540 PL5. Elena MILEVA, IPC, Sofia, Bulgaria 1540 – 1605 KN1. Maria VISA, University of Brasov, Romania 1605 – 1625 Coffee Break

Sessions 4/5. ORAL COMMUNICATIONS

Conference hall Chair: Anca DUȚĂ, Adriana BARAN

Library hall Chair: Diana CIOLACU, Alina IOVESCU

1625 – 1640 OC1. Geta DAVID, UTI OC2. Ioana Cătălina GÎFU, IMIPC 1640 – 1655 OC3. Daniel G. ANGELESCU, IMIPC OC4. Irina POPESCU, PPIMC 1655 – 1710 OC5. Monika GOSECKA, CMMS, OC6. Ludmila ARICOV, IMIPC 1710 – 1725 OC7. Maria COVEI, Univ. Brasov OC8. Andra HUMELNICU, PPIMC 1725 – 1740 OC9. Elena Livia SIMION, IMIPC OC10. Anca Ruxandra LEONTIES, IMIPC 1740 – 1755 OC11. Gabriela CÂRJĂ, UTI OC12. Ana Irina COCARȚĂ, PPIMC 1755 – 1815 Coffee Break


Chair: Piero BAGLIONI 1815 – 1855 PL6. Mariana PINTEALA, PPIMC, Iasi, Romania

Session 7. POSTERS Conference hall

Chair: Florica DOROFTEI, Claudiu GHIORGHIȚĂ, Anca LEONTIES, Gabriela STÎNGĂ

1855 – 1930 P1 – P23 Posters will be posted on the panels after participants’ registration and will remain exhibited during the entire conference period.

1930 – 2200 Dinner – Vanatorul Restaurant


Tuesday, May 17


Chair: Simona SCHWARZ, Stergios PISPAS 0900 – 940 PL7. Maria MIGUEL, Coimbra University, Portugal 0940 – 1020 PL8. Piero BAGLIONI, University of Florence, Italy 1020 – 1040 Coffee Break


Chair: Mariana PINTEALA, Björn LINDMAN 1040 – 1120 PL9. Svetlana BRATSKAYA, YPIOS, Vladivostok, Russia 1120 – 1200 PL10. Dan-Florin ANGHEL, IMIPC, Bucharest, Romania 1200 – 1220 Coffee Break


Chair: Teresa BASINSKA, Monika GOSECKA 1220 – 1300 PL11. Stanislaw SLOMKOWSKI, CMMS, Lodz, Poland 1300 – 1325 KN2. Anca DUTA, University of Brasov, Romania 1325 – 1500 Lunch


Chair: Maria MIGUEL, Geta DAVID 1500 – 1540 PL12. Teresa BASINSKA, CMMS, Lodz, Poland 1540 – 1605 KN3. Marcela MIHAI, PPIMC, Iasi, Romania 1605 – 1625 Coffee Break

Sessions 12/13. ORAL COMMUNICATIONS Conference hall

Chair: Maria VISA, Marcela MIHAI Library hall

Chair: Irina POPESCU, Daniel ANGELESCU

1625 – 1640 OC13. Gabriela STÎNGĂ, IMIPC OC14. Diana CIOLACU, PPIMC 1640 – 1655 OC15. Claudiu GHIORGHIȚĂ, PPIMC OC16. Alina IOVESCU, IMIPC 1655 – 1710 OC17. Monica MAXIM, IMIPC OC18. Anca PETROVICI, PPIMC 1710 – 1725 OC19. Diana Felicia LOGHIN, PPIMC OC20. Adriana BĂRAN, IMIPC 1725 – 1740 OC21. Marieta BALCAN, IMIPC OC22. Anca-Dana BENDREA,

PPIMC 1740 – 1800 Coffee Break


Chair: Elena MILEVA 1800 – 1840 PL13. Valeria HARABAGIU, PPIMC, Iasi, Romania 1840 – 1900 Conference Closing 1930 – 2200 Conference Dinner – Majestic Restaurant

Wednesday, May 18 1000 – 1100 Visit of the Palace of Culture 1100 – 1800 Excursion

Ruginoasa (Cuza Castle) – Hanul Ancutei – Miclauseni (Sturdza Castle)

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PLENARY LECTURES


PL 1. COMPETING FORCES IN CELLULOSE DISSOLUTION

Björn Lindman*, Luís Alves, Maria Miguel, Bruno Medronho Center of Chemistry and Chemical Engineering, Lund University, Sweden

Department of Chemistry, Coimbra University, Portugal *E-mail: [email protected]

Cellulose is difficult to dissolve and the use of cellulose in formulations, including the formation of

colloidal particles and fibers is limited by solubility limitations. Cellulose is known to be insoluble in water and in many organic solvents, but can be dissolved in a number of solvents of intermediate properties, like N-methylmorpholine N-oxide (NMMO) and ionic liquids (ILs) which, apparently, are not clearly related. It can also be dissolved in water at extreme pHs, in particular if a cosolute of intermediate polarity is added. The insolubility in water is often referred to strong intermolecular hydrogen bonding between cellulose molecules.

Revisiting some fundamental polymer physicochemical aspects (i.e. intermolecular interactions) a different picture is now revealed: cellulose is significantly amphiphilic and hydrophobic interactions are important to understand its solubility pattern [1].

In this work we try to expose the root of developing novel solvents for cellulose based on a critical analysis of the intermolecular interactions involved and mechanisms of dissolution. The hypothesis of cellulose insolubility induced by hydrophobic interactions has created significant interest. We also illustrate the association and precipitation of cellulose from rheology studies and how it can be affected by other amphiphilic compounds. Cellulose has a strong tendency to re-assemble when dissolved; this process is strongly affected by surfactants and other additives affecting hydrophobic interactions. References [1] B. Medronho, B. Lindman, Curr. Opin. Colloid Interface Sci. 2014, 19, 32-40.

mailto:[email protected]

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PL 2. SOL-GEL CHEMSITRY. BASIC RESEARCHES AND APPLICATIONS

Maria Zaharescu* ”Ilie Murgulescu” Institute of Physical Chemistry of the Romanian Academy, 202, Splaiul Independentei, 60021,

Bucharest, Romania *E-mail: [email protected]

Dedicated to the 150th anniversary of the Romanian Academy

Among the non-conventional wet chemical processes of obtaining oxide nanostructures, the sol-gel

method is one of the mostly used and studied as well. As it is well known, the sol-gel process represents the formation of an inorganic polymeric network by reactions in the solution at low temperatures. In the second step the inorganic amorphous polymers could be converted by adequate thermal treatments into glasses at temperatures far lower than the melting temperature of the corresponding oxides or in crystalline materials [1].

The most important step of the method is represented by the formation of the amorphous inorganic polymers in solution that allows properties tailoring of the resulted products [2]. However, this first step is the most difficult to be investigated, due to the high number of reactions that take place simultaneously leading to formation of a high number of molecular species.

In the presentation some information on the chemistry of the sol-gel processes, especially in the silica based systems, will be given based on gas chromatography coupled with mass spectrometry (GC-MS) [3, 4]. The influence of microwaves (MW) on the sol-gel process in doped and undoped TiO2 systems will be also discussed based on high pressure liquid chromatography (HPLC) investigations [5]. Preparation and complex characterization of oxide and hybrid nanostructures as films [6], powders (including 1D nanostructures) [6], nanocomposites and some of their possible applications will be also presented.

Figure 1. Sol-gel SiO2 powders [6]

Figure 2. Sol-gel SiO2 nano/ micro tubes [6]

Figure 3. Sol-Gel V-doped TiO2

films obtained in the presence of MW [5]

References [1] H. Schmidt, J. Non-Cryst. Solids 1988, 100, 51-64. [2] S. Sakka, K. Kamya, J. Non-Cryst. Solids 1982, 42, 31-46. [3] A. Jitianu, A. Britchi, C. Deleanu, V. Badescu, M. Zaharescu, J. Non-Cryst. Solids 2003, 319, 263-279. [4] A. Jitianu, M. Gartner, M. Zaharescu, D. Cristea, E. Manea. Mat. Sci. Eng. 2003, C23, 301-305. [5] L. Predoana, I. Stanciu, M. Anastasescu, J. M. Calderon-Moreno, M. Stoica, S. Preda, M. Gartner, M. Zaharescu, J. Sol-Gel Sci. Technol. 2016, DOI 10.1007/s10971-016-3972-9. [6] C. Anastasescu, M. Anastasescu, V.S. Teodorescu, M. Gartner, M. Zaharescu, J. Non-Cryst. Solids, 2010, 356, 2634-2640.



PL 3. INVESTIGATION OF THE ADSORPTION PROCESS OF HEAVY METAL IONS FROM AQUEOUS SOLUTIONS ON CHITOSAN

Simona Schwarz*, Mandy Mende

Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany *E-mail: [email protected]

Pollution by heavy metals is a serious threat for the environment, aquatic ecosystem, and human

health. Hence, heavy metals are nonbiodegradable and potentially toxic at very low concentrations. Chitosan is a good adsorbent for heavy metal ions in solution. We have used chitosan flakes, powder and beads with a degree of deacetylation of 90 % as adsorbent. First the dependence of the adsorption capacity on the adsorption time and the initial metal salt concentration was investigated. With increasing adsorption time as well as the initial metal salt concentration the adsorption capacity increases. Sulfate was the anion for all three salts investigated. Highest adsorption capacity was achieved for copper(II)ions on chitosan powder with 150 mg/L. Iron(II)- and nickel(II)ions adsorbed with an adsorption capacity of 80 mg/L.

By SEM analysis the formation of crystal-like structures was observed at higher adsorption time and higher initial salt concentration, when copper(II)sulfate and iron(II)sulfate were used. The adsorption of the nickel salt resulted in a smoother layer on the chitosan surface.

SEM-EDX analysis revealed that sulfate adsorbs on chitosan surface besides the metal cations used. In the case of copper and nickel sulfate all elements (i.e. copper, nickel, and sulfur) are uniformly distributed over the whole chitosan surface. This fact gives evidence that both cation as well as anion of the used salts adsorbed on chitosan surface. The distribution of the element iron on chitosan surface is not uniformly over the whole chitosan surface due to the rapid oxidation of the iron(II)ions on air resulting in partially adsorbed iron oxide. Sulfur was uniformly distributed on chitosan surface too. However, iron was only detected at certain areas on chitosan. The simultaneous adsorption of salt cations and anions used can be interpreted due to the investigated pH range between 5 and 6 in which the adsorption experiments were carried out. The coexistence of protonated and unprotonated amine groups allows that salt cations form chelate complexes with unprotonated amine groups and salt anions adsorb on chitosan surface by electrostatic interaction.

Figure 1. SEM images (5k x magnification) of chitosan surface pure and after heavy metal ion adsorption Acknowledgements This work was supported by the Central Innovation Programme (ZIM) of the Federal Ministry of Economy and Energy (BMWi) (KF 2022812RH1). The authors thank Heppe Biolog GmbH from Germany for the support of the materials and discussion and cooperativeness. References [1] M. Mende, D. Schwarz, S. Schwarz, proceedings of the word congress on civil, structural, and

environmental engineering, accepted, in press. [2] Mandy Mende, Dana Schwarz, Christine Steinbach, Regine Boldt, Simona Schwarz, Colloids and

Surfaces A: Physicochemical and Engineering Aspects, submitted

5 g/L CuSO4

5 g/L FeSO4 3 g/L NiSO4



PL 4. FUNCTIONAL NANOSTRUCTURES FROM AMPHIPHILIC BLOCK COPOLYMERS AND OTHER BUILDING BLOCKS

Stergios Pispas*

Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., 11635 Athens Greece Institute/Company, Street, Postal Code City, Country

*E-mail: [email protected]

Amphiphilic block copolymers have the ability to self-organize in a variety of nanometer scale

structures, usually as a response to changes in external physicochemical stimuli, as well as to interact with a variety of other building blocks, toward the formation of hybrid and functional nanostructures. These distinctive abilities allow the utilization of amphiphilic block polyelectrolytes, in particular, in a number of practical applications.

In this presentation we will discuss our resent results on the design and synthesis of novel amphiphilic block copolymers and block polyelectrolytes, their self-assembly in aqueous solutions and surfaces, and their interaction with proteins, nucleic acids, low molecular weight surfactants and inorganic nanoparticles, producing colloidal and surface nanostructures of different morphologies and functionalities [1-4]. The ultimate goal is to understand and master ways for controlling self-assembly of macromolecular materials and the creation of functional nanostructures able to find use in applications related to drug and gene delivery, enzymatic catalysis, biomimetics and biotechnology, and thin film designs. References [1] M. Uchman, S. Pispas, L. Kovacik, M. Stepanek, Macromolecules 2014, 47, 7081-7090. [2] E. Haladjova, S. Rangelov, Ch. B. Tsvetanov, V. Posheva, E. Peycheva, V. Maximova, D. Momekova, G. Mountrichas, S. Pispas, A. Bakandritsos, Langmuir 2014, 30, 8193-8200. [3] N. Pippa, M. Karayianni, S. Pispas, C. Demetzos, Int. J. Pharm. 2015, 401, 136-143. [4] A. Papagiannopoulos, A. Christoulaki, N. Spiliopoulos, A. Vradis, C. Toprakcioglu, S. Pispas, Langmuir 2015, 31, 685-694.

mailto:%[email protected]


PL 5. SMART COMPLEX FLUIDS BASED ON ANTENNARY OLIGOGLYCINES

Elena Mileva*, Anna Gyurova, Stefan Stoyanov, Dimi Arabadzhieva, Ljubomir Nikolov Institute of Physical Chemistry, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria


Aqueous systems based on synthetic antennary oligoglycines have high potential for biomedical and

water-purity-control applications. The oligoglycine molecules self-organize into supramolecular assemblies (tectomers) in aqueous media, forming bulk hydrophilic nanoplatforms, vesicles, etc. The innate reason for the self-organization is the onset of highly cooperative arrangement of intra- and intermolecular hydrogen bonds. The properties of these smart complex fluids may be finely tuned by changes of pH and/or the addition of charged entities (low molecular mass electrolytes, or high molecular mass substances).

A combined procedure is developed, including the registration of inception and stability of the bulk aggregates of various sizes and charges, examination of the properties of the interfacial layers at the solution/air boundary and the drainage characteristics of microscopic foam films. Due to the specific structure and properties of the obtained tectomers, these complex fluid systems may be applied for the entrapment of charged nanospecies of various origin. Thus the obtained results suggest that the self-assembled nanostructures of antennary olygoglycines may be implemented e.g. as indicators and captive agents for trace quantities of dangerous substances of biological origin (endotoxins) in aqueous media [1]. Acknowledgements The investigation is performed under the umbrella of COST Action MP 1106 “Smart and green interfaces - from single bubbles and drops to industrial, environmental and biomedical applications”. S.S. is grateful to the World Federation of Scientists for a PhD Scholarship. References [1] A. Gyurova, S. Stoyanov, E. Mileva, Colloids and Surfaces A 2014, 460, 130-136.



PL 6. NON-VIRAL DELIVERY SYSTEMS FOR GENE THERAPY

Mariana Pinteala*, Bogdan C. Simionescu ”Petru Poni” Institute of Macromolecular Chemistry, 41A Gr. Ghica Voda Alley, Iasi, Romania



Polycationic compounds, especially those based on hyperbranched poly(ethylene imine) (PEI), have

been extensively studied as gene transfer vehicles due to their outstanding capacity to condense nucleic acid molecules via electrostatic interaction and due to their “proton sponge effect” that allows polyplexes to be released in the cytosol form. The present study focuses on the synthesis of different non-viral vectors, using low molecular mass PEI (2 kDa) connected to a core molecule. Due to their high biocompatibility, fullerene C60, tetramethylcyclotetrasiloxane (cD4

H) and β-cyclodextrine (β-CD) were selected as core molecules. Transfection was monitored on HEK cell line by using an EYFP plasmid encoding a green fluorescent protein. Figure 1. Schematic representation of nanovector complexation with plasmid DNA.

The corresponding nanovectors – C60-PEI, C60-PEG-PEI, cD4

H-AGE-PEI and β-CD-PEG-PEI were investigated as concerns plasmidial DNA (pDNA) packaging by DLS, zeta potential measurements, TEM / AFM for size and morphology determination and gel retardation assay to assess the packing capacity of the vectors at different N/P ratios (the ratio between nitrogen from PEI and phosphorus from DNA). Biological tests on HEK 293 cell culture were performed to quantify the transfection yield, both as transfected cell percentage and protein express (EYFP) percentage, and to evaluate cell viability after

treating with polyplex solutions. The highest transfection yields were recorded for cD4

H-AGE-PEI/pEYFP at N/P=200 (~36%). The PEGylated compounds C60-PEG-PEI and β-CD-PEG-PEI exhibit a lower percent of transfected cells, of 10% and 14%, respectively (for N/P ratios between 100÷200), but show an average fluorescence intensity (MFI) similar to that of the commercial transfection agent (Superfect®, Qiagen) used as positive control. All investigated compounds display a good cytocompatibility, the PEGylated ones additionally inducing a significant cell proliferation, even at higher N/P ratios. Acknowledgements This work was supported by the Romanian National Authority for Scientific Research grant, CNCS – UEFISCDI, project number PN-II-ID-PCCE-2011-2-0028 and the H2020 ERA Chairs Project – SupraChem Lab Laboratory of Supramolecular Chemistry for Adaptive Delivery Systems ERA Chair initiative (contract no: 667387).



PL 7. DNA IS A HIGHLY CHARGED AMPHIPHILIC POLYMER THAT ASSOCIATES STRONGLY WITH CATIONIC SURFACTANTS

Maria Miguel*, Björn Lindman, Rita Dias, Carmen Morán, Diana Costa

Department of Chemistry, Coimbra University, Coimbra, Portugal *E-mail: [email protected]

As a strongly negatively charged polyelectrolyte, DNA associates strongly with cationic cosolutes,

such as surfactants, lipids, polymers and proteins; all these systems are characterized by a strong associative phase separation. Cationic lipids and surfactants are efficient in compacting DNA and can also be efficient transfection agents. An overview of DNA-surfactant interactions is presented illustrating the binding of surfactants to DNA in bulk and consequences in terms of phase behavior and compaction. Phase diagrams show a strong associative phase separation, with two-phase regions increasing strongly in size with the increase of the cationic surfactant chain length. Techniques used for the characterization of DNA-surfactant complexes include small-angle X-ray scattering (SAXS), light scattering, nuclear magnetic resonance (NMR), cryogenic transmission electron microscopy (cryo-TEM), and fluorescence microscopy. Cationic surfactants are very efficient in compacting DNA, thus changing the extended DNA molecules into compact globules. We are also interested in combining surfactants to control compaction and we discuss the de-compaction induced by anionic surfactants and in general the interaction of DNA with mixed cationic-anionic systems. A general understanding of the interactions between DNA and oppositely charged agents, and in particular of their phase behaviour, has provided a basis for developing novel DNA-based materials, including gels and gel particles.

In particular, we describe the preparation of covalent DNA gels obtained by cross-linking of linear DNA molecules, and describe their swelling-deswelling behavior. It is found that covalent gels offer novel opportunities for monitoring DNA-cosolute interactions. A weak deswelling is obtained with simple 1:1 electrolytes, whereas the deswelling becomes much more important with increasing valency of the counterion. For multivalent counter-ions such as in polyelectrolytes and proteins a strong deswelling is observed for low concentrations. Cationic surfactants give a very strong deswelling but only above the critical micelle concentration (cmc) where highly charged aggregates form. This gel deswelling is reversible as can be learnt from the observation that gels compacted with cationic surfactant reswells to the original volume on adding an anionic surfactant. Recently, also plasmid DNA gels have been prepared and investigated with respect to their swelling and deswelling in aqueous solution containing different additives, such as metal ions, surfactants, polyamines, proteins and drugs. The photodisruption of pDNA gels was used as a strategy to promote controlled pDNA release. Cell viability assays also suggest that the pDNA gels are biocompatible.

Based on the associative phase separation and interfacial diffusion, we have also developed a way to prepare DNA gel particles without adding any kind of cross-linker or organic solvent; and the preparation of DNA particles, by just mixing DNA with surfactant, polycation and protein solutions, has been achieved. Surface morphology, the degree of DNA entrapment, the swelling/deswelling behavior and kinetics of DNA/protein release are also described. The stronger interaction of ssDNA, as compared with dsDNA, suggests the important role of the amphiphilicity of DNA on the interactions. These DNA gel particles were also assessed for haemolysis.

It is our belief that these findings may increase the potential of these systems as delivery and co-delivery systems.



PL 8. PHYSICAL AND CHEMICAL GELS FOR FINELY CONTROLLED CLEANING OF CULTURAL HERITAGE

Piero Baglioni*

Department of Chemistry& CSGI, University of Florence, Via della Lastruccia 3 - Sesto Fiorentino, 50019 Florence, Italy


Works of art and artifacts that constitute our cultural heritage are subject to deterioration. Their

surfaces interacting with the environment are the most prone to aging and decay; accordingly, soiling is a prime factor in the degradation of surfaces, chemical and mechanical degradation are often associated to soiling and lead to the disfigurement of a piece of art. The effects of these processes are usually strongly amplified by the protective coatings (mainly acrylic and vinyl polymers), applied in previous restoration treatments. In the past years we pioneered the synthesis and the application of several advanced systems for the consolidation and the cleaning of works of art, as hydroxides nanoparticles (wall paintings, paper and wood), microemulsions and chemical/physical gels.

Micellar solutions and microemulsions constitute very efficient systems for the removal of acrylic,

vinyl and alkyl polymers, dust or grime/soil. These systems (as well as neat solvents used in "traditional" conservation) can be confined into chemical and physical gels having proper nano-domains for the upload or the delivery of compounds from/to the work of art. For example, a fine control of the cleaning procedure can be obtained even for challenging cleanings as water sensitive works of art, where the cleaning can be achieved by using water confined into gels, and leaving no residues on the works of art. Example from the application of these new systems/methods to the cleaning of classic and modern/contemporary art (J. Pollock, Picasso, Castellani, Sironi, pressure sensitive tapes, Arienti, etc.) will be highlighted [1-8]. References 1) P. Baglioni, E. Carretti, D. Chelazzi, Nat. Nanotechnol. 2015, 10, 287-290. 2) P. Baglioni, D. Chelazzi, R. Giorgi, Nanotechnologies in the Conservation of Cultural Heritage - A compendium of materials and techniques, Springer, 2015 3) P. Baglioni, D. Chelazzi, Nanoscience for the Conservation of Works of Art, Royal Society of Chemistry, 2013. 4) M. Baglioni, D. Berti, J. Teixeira, R. Giorgi, P. Baglioni, Langmuir 2012, 28, 15193–15202. 5) M. Baglioni, R. Giorgi, D. Berti, P. Baglioni, Nanoscale 2012, 4, 42–53. 6) M. Baglioni, D. Rengstl, D. Berti, M. Bonini, R. Giorgi, P. Baglioni, Nanoscale 2010, 2, 1723–1732. 7) R. Giorgi, M. Baglioni, D. Berti, P. Baglioni, Acc. Chem. Res. 2010, 43, 695–704. 8) E. Carretti, E. Fratini, D. Berti, L. Dei, P. Baglioni, Angew. Chem. Int. Ed. 2009, 48, 8966−8969.



PL 9. GREEN SYNTHESIS OF GOLD NANOPARTICLES USING CHITOSAN AND ITS

DERIVATIVES

Alexander Pestov1,2, Svetlana Bratskaya2*

1I. Ya. Postovsky Institute of Organic Synthesis, Ural Branch of RAS, 20, S. Kovalevskoy str., Yekaterinburg 620990, Russia

2Institute of Chemistry, Far East Branch of RAS, 159, prosp.100-letiya Vladivostoka, Vladivostok 690022, Russia


Biogenic synthesis of metal nanoparticles attracts an increasing interest due to its compliance with

the principles of “green” chemistry, non-toxicity, and biocompatibility of fabricated materials. The polycation nature of chitosan is particularly favorable for gold nanoparticles synthesis, since, on the one hand, chitosan effectively binds [AuCl4]– ions, and on the other hand, stabilizes formed nanoparticles due to the high affinity of N-containing functional groups to the surface of metallic gold.

In green synthesis of gold plasmon nanoparticles and nanodots, the efficient coordination of precursor ion Au(III) by the polymer at the first stage of the process is extremely important [1]. Moreover, the balance of coordinating and reducing moieties is a crucial factor that determines the size of gold nanoparticles formed in biopolymer solutions without external reductants. Despite numerous reports on chitosan and its derivatives application for Au nanoparticles synthesis, neither the mechanism of Au(III) ions reduction by chitosan nor the chemical structure of the reaction by-products has been investigated in details. The influence of functional fragments in chitosan macromolecule on the morphology of the gold nanoparticles and mechanism of Au(III) reduction also remains unknown.

Here we present comprehensive study of Au(III) reduction mechanism by chitosan and the series of its N-derivatives containing N-heterocyclic substituents. The data obtained using UV-vis spectrophotometry, viscosimetry, colloid titration, and 1H and 13C NMR spectroscopy enabled us to propose mechanism of Au(III) reduction by chitosan and its derivatives. Regardless of the type of functionality in substituted chitosan formation of gold nanoparticles starts with complexation of Au(III) and hydrolysis of adjacent glycoside bond. The products of hydrolysis act as main reducing species. Reduction rate and size of the gold nanoparticles strongly depend on polymer-Au(III) complex stability and metal/ligand ratio.

Water soluble luminescent gold nanoparticles with average size 2.3 nm were synthesized using N-(4-imidazolyl)methylchitosan (IMC) as both reducing and stabilizing agent. Reduction of Au(III) to gold nanoparticles in IMC solution was a slow process, in which coordination power of biopolymer controls both reducing species concentration and gold crystal growth rate. Gold nanoparticles formed in IMC solution do not manifest surface plasmon resonance, but exhibit luminescence at 375 nm under UV light excitation at 230 nm. Due to biological activity of imidazolyl-containing polymers and their ability to bind proteins and drugs, the obtained ultra-small gold nanoparticles can find an application for biomolecules detection, bio-imaging, drug delivery, and catalysis.

Acknowledgements Financial support from Russian Science Foundation (project № 14-13-00136) is gratefully acknowledged. References [1] B.A. Rozenberg, R. Tenne, Prog. Polym. Sci. 2008, 33, 40–112.



PL 10. MICROEMULSIONS FROM ENHANCED OIL RECOVERY TO HYBRID ENGINE FUELS: AN OVERVIEW

Dan-Florin Anghel*, Marieta Balcan, Monica Elisabeta Maxim, Florentina Cristina Mihailescu

Colloid Chemistry Laboratory, ‘Ilie Murgulescu’ Institute of Physical Chemistry, Romanian Academy, 202 Spl. Independentei, Post Office 12, P.O. Box 194, 060021 Bucharest, Romania

*E-mail: [email protected]; [email protected]


Enhanced oil recovery (EOR) and hybrid engine fuels (HEF) are nowadays topics of high worldwide

interest. They are tightly related because have the same source, the crude oil. It is important to stress that human being did a lot of achievements during his evolution, but is still unable to produce crude oil. Crude oil is the most important resource of energy available on earth. It is processed to diesel, petrol and jet fuels for cars, trucks, ships, planes, stationary electrical generators, etc. The increased demand of fuel, the indiscriminate extraction and depletion of crude oil reservoirs entailed shortages in supply and fluctuant prices on market [1, 2]. The interest in EOR comes from the fact that the current primary and secondary extraction technologies take out only one-third of the oil-in-place. The rest remains trapped into the pores of reservoir rock. Therefore, the recovery of this huge amount of crude oil is a major task.

To achieve this goal physical and chemical processes have been proposed. The chemical processes that have been applied in the field are the floodings such as: alkaline, polymer, surfactant, polymer/surfactant and microemulsion. Microemulsion (ME) is advantageous because it displaces the crude by lowering the oil/water interfacial tension (σow), to ultra-low values (< 10-3 mN/m), and controls the mobility. As a consequence, ME is able to recover large amounts of crude oil, otherwise unrecoverable. Therefore, a very important topic is design and formulation of optimal microemulsions. On the other hand, the interest in AEF is in turn generated by reservoir depletion and by the damage of environment as well. Since diesel is a major contributor to these issues, many efforts are now done to replace it. A promising alternative towards this end are microemulsions (ME) with neat diesel, diesel-vegetable oil (VO) blends, or with VO. Vegetable oils are similar to diesel, have no sulfur and aromatics, are biodegradable, renewable and eco-friendly. Their main disadvantages are the low volatility and high viscosity. These problems can be overcome by dilution, pyrolysis, and trans-etherification or by ME. ME allow partial or total substitution of diesel with vegetable oil, and bring water in fuel, which is benefic both for engine and environment. This talk is devoted to microemulsions for EOR and HEF. It is focused on preparation by means of phase diagrams. Emphasis is put on handling the phase behavior, oil/water interfacial tension, particle size of the dispersed phase, solubilization of oil and water (SPo and SPw), viscosity, cloud and pour point, which are key parameters in formulating optimal ME. The microemulsions were obtained with various surfactants, surfactant-cosurfactant blends, oils and waters. The results obtained reveal that one-phase ME decreases with the hydrophobicity of surfactant and by salt, but increases for surfactant-cosurfactant mixtures. For a given system, increasing the salt concentration brings about the Winsor (W) sequence: WI ↔ WIII ↔ WII. In the WIII systems, σow is minimal, whereas SPo, SPw and the particle size of MF are maximal. These criteria apply to both EOR and HEF microemulsions. In the first case, the obtained ME were used in two successful field experiments. In the case of HEF microemulsions, additional criteria like viscosity, calorific power, cloud and pour points have to be met. The designed microemulsions have slightly higher viscosities than neat diesel, whereas the calorific power, cloud and pour points are comparable to it. The presentation is a useful approach to design optimal microemulsions for enhanced oil recovery as well as hybrid fuels for diesel engine. Acknowledgements The research for this paper has been carried out within the Functional Complex Colloids Program of the ‘Ilie Murgulescu’ Institute of Physical Chemistry, financed by the Romanian Academy. The authors gratefully acknowledge the support of the EU (ERDF) and Romanian Government allowing for acquisition of research infrastructure under POS-CCE O 2.2.1 project INFRANANOCHEM, No. 19/01.03.2009. This work is also supported by the PN-II-ID-PCE-2011-3-0916 Exploratory Research Project. References [1] US Energy Information Agency. https://www.eia.gov/forecasts/steo/report/prices.cfm. [Accessed: 2016-02-10]. [2] Bloomberg Business, http://www.bloomberg.com/energy [Accessed: 2016-02-10].



https://www.eia.gov/forecasts/steo/report/prices.cfm

http://www.bloomberg.com/energy


PL 11. POLYSILOXANE MICROSPHERES AND THEIR CERAMIC DERIVATIVES

Stanislaw Slomkowski*, Witold Fortuniak, Julian Chojnowski, Piotr Pospiech, Urszula Mizerska Center of Molecular and Macromolecular Studies, Polish Academy of Sci., Sienkiewicza 112, 90-363 Lodz, Poland


Lecture will present a new route to synthesis of all-polysiloxane microspheres and their derivatives

with reactive organofunctional groups. The pristine polysiloxane microspheres could be pyrolized yielding the crack-free silicon oxycarbide particles.

The all-polysiloxane microspheres containing a large number of silanol groups were obtained by a

process including combination of the four competitive/consecutive reactions of polyhydromethylsiloxane

(PHMS) catalyzed by a Pt(0) complex in an aqueous emulsion process [1]. These reactions included (i)

hydrosilylation of olefinic bond of a cross-linker with the SiH group on the polymer, (ii) hydrolysis, and in

some cases alcoholysis, of the SiH bond in the polymer and (iii) dehydrogenative condensation of the SiOH

group formed in the hydrolysis with the SiH group. A solution of PHMS with divinyltetramethyldisiloxane

(DVTMS) cross-linker together with the catalyst was mechanically emulsified with water. The polymer

cross-linking and the silanol formation occurred in the formed emulsion. Usually the preliminary

hydrosilylation was carried out before emulsification. In this way the vinylsiloxane was grafted on PHMS. In

the emulsion process a large number of SiH groups on PHMS were transformed into SiOH hydrophilic

groups. This reaction did occur both, on the surface of microspheres and in their bulk. The cross-linking of

PHMS resulted from hydrosilylation of vinyl groups grafted on the polymer and by dehydrogenative

condensation of the SiH groups with the silanol groups which are formed on PHMS. The obtained

microspheres were modified by reactions with reactive silanes containing organofunctional groups (vinyl,

amine and epoxide).

The preceramic microspheres, with average diameters from 7.6 to 56 μm, were pyrolyzed at various

temperatures. Results of the first studies of this subject were published in our recent paper [2]. In the lecture

we will provide results of detailed characterization of the pyrolyzed microspheres and their precursors based

on 29Si and 13C MAS NMR, FTIR spectroscopy, and elemental analysis. The structures of the microspheres

were examined by SEM. Some samples were also investigated by XRD and Raman spectroscopy. All of

the synthesized preceramic microspheres retained their regular spherical shapes during pyrolysis at

temperatures of up to 1200 °C. Heating at 1000 °C and 1200 °C yielded amorphous silicon oxycarbide

ceramic materials with segregated free carbon domains. The chemical and physical structures of the

obtained ceramic microspheres were significantly influenced by the modification of the preceramic

materials.

The above-described simple method allowed to obtain a library of silicon containing particles, from

soft, swellable polysiloxane microspheres with functional groups suitable for immobilization of catalysts, in

particular enzymes.

Acknowledgements The financial support from NCN grant 2013/11/B/ST5/01615 is highly appreciated. References [1] W. Fortuniak, J. Chojnowski, S. Slomkowski, P. Pospiech, J. Kurjata, Polymer 2013, 54, 3156-3165. [2] W. Fortuniak, J. Chojnowski, S. Slomkowski, A. Nyczyk-Malinowska, P. Pospiech, U. Mizerska,

Mater. Chem. Phys. 2015, 155, 83-91.



PL 12. ASSEMBLIES OF COLLOIDAL HYDROPHILIC PARTICLES CONTAINING POLYGLYCIDOL: PREPARATION, CHARACTERIZATION, APPLICATIONS

Teresa Basinska*, Monika Gosecka, Patrycja Komar, Stanislaw Slomkowski

Center of Molecular and Macromolecular Studies,Polish Academy of Sciences, H. Sienkiewicza 112, 90-363 Lodz, Poland,


Nowadays assemblies of colloidal particles are manufactured on a small or larger scale for research

and practical purposes; applications in optical or electronic devices, biosensors, tissue engineering or cells cultures, medical diagnostic tests etc. For the all above-mentioned applications the controlled arrangement of nano- or microparticles is required and the properties of the particles should be tailored for the final material needs. In various biomedical applications of colloidal materials the particles with the hydrophilic shells and reactive groups suitable for binding biomolecules are needed. This is because these particles usually should carry-on immobilized proteins (antigens/antibodies) which acting in body fluids it should be “invisible” for all biomolecules other than the targeted ones. The particles with two kinds of shape as well as and their assemblies were investigated. Namely, the core-shell spherical particles with polystyrene cores and shells containing hydrophilic polyglycidol segments (P(S/PGLy) and particles with similar chemical composition and core-shell structure but with the ellipsoidal shapes. The latter were formed from the spherical ones [1].

The lecture will present results of the studies of relations between chemical structure, hydrophilicity and shape of the particles and morphology of their assemblies on patterned surfaces. Controlled arrangement of attached particles can be achieved in this way [2]. Moreover, we were interested in formation of 3-dimensional assemblies of particles known as colloidal photonic crystals with specific maxima of diffracted visible light (Bragg peaks). The characteristic features of the colloidal crystals composed of the core-shell poly(styrene/polyglycidol) particles will be discussed. Particularly interesting are 3-D assemblies of ellipsoidal particles, which form structures similar to the liquid crystals.

The methods of particles deposition will be presented, and the representative examples of hydrophilic spherical and ellipsoidal particle assemblies on surfaces with amine, hydroxyl and carboxyl groups will be discussed. The examples of crystalline materials obtained from the title particles will be presented.

Figure 1. Assemblies of spherical (Dn=300 nm, fPGLy=27.8 mol %) and ellipsoidal P(S/PGLy) particles deposited on silicon wafer containing anchored amine groups.

Acknowledgements The work was financially supported by National Center of Science grant nr UMO-2014/13/B/ST5/04376.

References [1] H. Shin, C. Kim. Colloid Polym. Sci. 2012, 290,1309–1315. [2] A.Yu. Menshikova, B. M. Shabels, N.N. Shevchenko, A.G. Bazhenova, A.B. Pevtsov, A.V. Sel’kin, A.Yu. Bilibin. Colloids Surf., A: Physicochem. Eng. Asp. 2007, 298, 27-33.



PL 13. HYBRID MATERIALS BUILT OF SILICON-BASED POLYMERS

Valeria Harabagiu*, Liviu Sacarescu ”Petru Poni” Institute of Macromolecular Chemistry, 41A Aleea Grigore Ghica Voda, 700487 Iasi, Romania



Polysiloxane and polysilanes are themselves by nature hybrid polymeric materials where organic

substituents are linked to inorganic Si-O-Si, respectively -Si-Si- chains. The chemical structure of both chain skeleton and organic substituents to silicon atoms is strongly influencing their properties. Thus, while the polydimethylsiloxanes are characterized by high flexibility, hydrophobicity and thermal resistance, the polysilanes are well known for the delocalization of σ-electrons along the polymeric chain, thus inducing electro-optical and semiconducting properties in the doped state. The coupling of silicon-based polymers with organic or inorganic moieties will further increase the spectrum of their properties and application.

The presentation deals with the preparation and properties of polysiloxane and polysilane (co)polymers or networks [1-5], inclusion complexes of polysiloxanes into cyclodextrin macrocycles [3] and metal (or metal oxide)-polymer nanoparticles [4-6]. Figures 1 and 2 show some examples of the discussed hybrid systems.

Figure 2. Polysilane assisted synthesis of gold

nanoparticles Acknowledgements: the work was partially supported by of the project STHEMWOTB, contract MENCS-UEFISCDI no.59/2014. References [1] A.C. Humelnicu, V. Harabagiu, C.A. Peptu, M.-M. Leon, F. Mitu, E. Cojocaru, A. Boca, B.I. Tamba, Curr. Pharm. Design 2015, 21, 6125-6139. [2] M. Soroceanu, A.I. Barzic*, I. Stoica, L. Sacarescu, V. Harabagiu; Express Polym. Lett. 2015, 9(5), 456-468. [3] M. Soroceanu, L. Sacarescu, E.G. Hitruc, C. Ursu, V. Harabagiu, Int. J. Polym. Anal. Charact. 2014, 19(6), 482-488. [4] C. Miron, M. Balan, L. Pricop, V. Harabagiu, I. Jepu, C. Porosnicu, C.P. Lungu, Plasma Proc. Polym.

2014, 11(3), 214-221. [5] V. Totolin, N. Ranetcaia, V. Hamciuc, N. Shore, N. Dörr, C. Ibanescu, B.C. Simionescu, V. Harabagiu, Tribology Int. 2013, 67, 1-10. [6] L. Sacarescu, M. Simionescu, G. Sacarescu, V. Harabagiu, J. Inorg. Organomet. Polym. Mater. 2013, 23(3), 621-628. [7] G. Sacarescu, E. Taran, B.C. Donose, M. Simionescu, V. Harabagiu, L. Sacarescu, Polym. Int. 2012, 61(12), 1726–1732.

Figure 1. Polysiloxane – cyclodextrin polyrotaxanes



KEYNOTE LECTURES


KN 1. NANOCOMPOSITE WO3-TIO2/FLY ASH WITH DUAL FUNCTIONALITY IN SIMULTANEOUS REMOVAL OF POLLUTANTS FROM WASTEWATER

Visa Maria*, Chelaru Andreea, Anca Duta

Transilvania University of Brasov, Product Design and Environment, Colina Street, Brasov, Romania *E-mail: [email protected]

The present research focused on the preparation of TiO2-WO3/FA composite with activity in

adsorption and photocatalysis for to remove two industrial dyes (used in textile industry) and heavy metals under UV light. The composites were prepared from fly ash and semiconductors by hydrothermal method for achieving a homogeneous distribution of the components within the composite. Fly Ash resulted from burning coal or biomass is a mixture of oxides with unburned carbon and other minority inorganic compounds thus has a predominant negative surface charge and represents a promising adsorbent for wastewater with complex composition.

The individual WO3 and TiO2 nanocrystals were obtained either by sol-gel. The produced nanomaterials were characterized in terms of crystallinity (XRD) and surface properties: morphology and composition (AFM, SEM, EDS) wettabiliry (contact angle measurements), specific surface (BET) and FTIR. Major differences in their photocatalytic/adsorption activity performance depended on the nature of the precursors and the synthesis pathway.

The adsorption capacity and photocatalytic properties of the composites were tested on mono- and multi-pollutants systems containing two dyes (Bemacid Blau -BB and Bemacid Rot- BR) and one heavy metal ion-Cu2+, the optimized process conditions were identified. The initial and residual dye concentrations in the aqueous solution was analyzed by UV-VIS spectrometry (Perkin Elmer Lambda 25), on the calibration curve registered at the maximum absorption peaks of BB (λ=629 nm), and BR (λ=501 nm), while the heavy metal concentration was analyzed by AAS (Analytic Jena, ZEEnit 700), at λCu =324.75nm,respectively

The results indicate better removal efficiencies using the novel composite material in the combined adsorption and photocatalysis, as compared to the separated processes. Dyes removal was significantly enhanced in the photocatalytic process by adding hydrogen peroxide.

The parameters (contact time, amount of substrate and initial concentration of the pollutants) were optimized for obtaining a maximum efficiency and were further used in thermodynamic and kinetic studies, comparatively discussed with the photocatalysis optimized operating parameters.

The pseudo second order kinetics model best fitted the experimental data, both in the adsorption and in the combined process. The kinetic parameters were calculated and correlated with the properties of the composite substrate. Acknowledgements This work was supported by a grant of the Romanian National Authority for Scientific Research, CNCS –

UEFISCDI, project number PN-II-RU-TE-2012-3-0177/2013.



KN 2. CATION – SURFACTANT INTERACTIONS IN SMALL DROPLETS UNDER A TEMPERATURE GRADIENT

Anca Duta*

Transilvania University of Brasov, R&D Centre: Renewable Energy Systems and Recycling, Eroilor 29, 50036, Romania, *E-mail: [email protected]

The chemical deposition techniques allow obtaining thin films in low cost, up-scalable processes.

Spray pyrolysis deposition (SPD) is one of the already used method, implemented at industrial level, basically for coating applications. However, in solar-energy conversion systems, the semiconductor thin films requires more accurate control of composition, crystallinity, polymorphism, morphology and wetting properties to get the targeted output properties (optical and/or electric). These set of properties should be mainly reached during deposition and can be further improved through thermal treatments. Thus, controlled nucleation and growth is of outmost importance and fine tuning can be done using templating agents, as surfactants or polymers. One specific feature of SPD that raises challenges in properties control is related to the technique as such: the small drops of the atomized precursor system continuously increase their temperature while approaching the heated plate where pyrolysis occurs, and, according to their volatility, the droplets will shrink, increasing the actual concentrations of all components. Thus significant changes occur between the precursor cation - surfactant(s) interactions, changing the template and modifying the nucleation pattern (and kinetics) during deposition (Fig. 1).

Fig. 1. Influence of the surfactant concentration on the cation-SDS interactions in SPD

The paper discusses these aspects considering the thermodynamic correlations and analyses the control properties in two common precursor systems involving SDS; the cation influence (size, polarizability) is also outlined based on morphology results, for the TiO2 and WO3 as deposited thin films.

Acknowledgements This work was performed using financial support provided by the Project: PNII-PCCA, NANOVISMAT ctr. No. 162/2012.

mailto:%[email protected]


KN 3. POLYELECTROLYTE COMPLEXES AS COLLOIDAL DISPERSION COMPLEX TEMPLATES FOR CaCO3 CRYSTALS GROWTH

Marcela Mihai*, Stefania Racovita, Florica Doroftei, Ana-Lavinia Matricala, Cristian Barbu-Mic

“Petru Poni” Institute of Macromolecular Chemistry, 41A Grigore Ghica Voda Alley, 700487, Iasi, Romania *E-mail: [email protected]


An important method of biomimetic synthesis consists in the use a soft organic templates to control

the morphogenesis of inorganic materials with complex forms. Due to its abundance in nature [1], calcium carbonate – a biocompatible inorganic material – received considerable interest for industrial applications (coatings, fillers, and components of drug and personal care formulations), and in environmental applications, for its potential application in carbon-capture [2]. In addition to a high natural abundance, it exhibits a unique combination of properties which include pH sensitive decomposition, nontoxicity, biocompatibility, low cost, and thus it is considered as a potential delivery vehicle for compounds such as drugs and proteins [3]. Even if numerous studies deal with polyanions control of CaCO3 growth and with the polyanions used in this study, to our knowledge, except our previous study, no reports on the use of in-situ mixing of complementary polyelectrolytes as templates for controlling CaCO3 crystals growth have been published. There, we investigated composite calcium carbonate microparticles formation from supersaturated inorganic aqueous solutions in the presence of some strong/weak anionic polymers or nonstoichiometric polyelectrolyte complexes (NPEC) dispersions with excess anionic charges, and with low molar ratio between charges (0.2 and 0.4, respectively) [4].

The aim of this study was to follow the effect of mixed anionic/cationic polyelectrolytes on the crystallization of calcium carbonate in supersaturated solutions as compared to polyanion based-CaCO3 composite structures [5]. The method of introducing the polycation in the crystallogenesis of calcium carbonate has been also investigated: in-situ mixing of complementary polyelectrolytes or using nonstoichiometric polyelectrolyte complexes. For this purpose three polyanions, which contain weak – polyacrylic acid sodium salt, PAA – or strong anionic groups – poly(sodium 4-styrenesulfonate), PSS and poly( sodium vinylsulfonate), PVS – and poly(diallyl-dimethylammonium chloride), PD as polycation were used. Different molar ratio between complementary polyelectrolytes (n+/n-) were used in CaCO3 composite synthesis – from 0 (just polyanions) to 0.8. Composite particles characteristics as a function of polyanions structure and the preparation mode were evidenced by scanning electron microscopy (SEM) (Figure 1), FTIR-ATR spectroscopy, and energy dispersive X-ray diffraction (EDAX).

CaCO3//PSS CaCO3//PSS/PD CaCO3//NPEC(PSS/PD)

Figure 1. SEM images and schematic representation of composite microparticles based on CaCO3 and different polymeric templates

The particles morphology after dialysis against ethylenediamine tetraacetic acid (EDTA) has been

also followed, as a function of molar ratio between complementary polyelectrolytes and preparation mode. Acknowledgements This work was supported by a grant of the Romanian National Authority for Scientific Research and Innovation, CNCS – UEFISCDI, project number PN-II-RU-TE-2014-4-1433. References [1] F. C. Meldrum, H. Colfen, Chem. Revs. 2008, 108, 4332-4432 [2] A. C. Mitchell, K. Dideriksen, L. H. Spangler, A. B. Cunningham, R. Gerlach, Environ. Sci. Technol.

2010, 44, 5270-5276. [3] D. V. Volodkin, N. I. Larionova, G. B. Sukhorukov, Biomacromolecules 2004, 5, 1962-1972. [4] M. Mihai, S. Schwarz, F. Simon, Cryst. Growth Des. 2013, 13, 3144−3153. [5] M. Mihai, S. Schwarz, F. Doroftei, B. C. Simionescu, Cryst. Growth Des. 2014, 14, 6073−6083.

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ORAL COMMUNICATIONS


OC 1. HYBRID BIOMATERIALS - CHALLENGES AND OPPORTUNITIES

Geta David1*, Tudor Vasiliu1, Daniel Tampu2, Dragos Peptanariu2, Cristina Uratu2 1”Gh. Asachi” Technical University of Iasi, Bd. D. Mangeron, 71A, 700055 Iasi, Romania

2“Petru Poni” Institute of Macromolecular Chemistry, Aleea Grigore Ghica Voda 41A, 700487 Iasi, Romania *E-mail : [email protected]

Combining different materials in order to achieve the appropriate performances requiered for the

applications in the envisaged domains is one of the strategies used to obtain biomimetic materials for biomedical uses, one of the topical research goal. Biocomposites or inorganic/organic (nano)composites are amongst the most studied biomaterials. However, to reach the envisaged level of functionality, together with hybrid material stabilityand processing ability, is often a real challenge, beginning with the selection of the components and of the preparative method.

In this context, here some results are presented on the preparation, characterization and possible uses of hybrid materials generated by combining the most important components of the extracellular matrix -collagen and glycosaminoglycans- and synthetic polymers, in order to yield functionality, biocompatibility, together with processability, tailored mechanical stability and degradability. Making use of the versatility of such complex materials, these were trandformed in 3D matrices with tuned chemical, physical and morphological characteristics, or in multifunctional multilayered nanoparticles (Scheme 1). Preliminary data on the inclusion of non-viral gene carriers in porous 3D-matrices to give combined gene delivery systems, considered the most promising for clinical application, are presented.

Scheme 1. Hybrid biomaterials based on natural and synthetic polymers and nano-hydroxiapathite.

Acknowledgements This work was supported by a grant of the Romanian National Authority for Scientific Research, CNCS – UEFISCDI, project number PN-II-ID-PCCE-2011-2-0028.



OC 2. HYDROPHOBIZATION OF GLASS SURFACE BY ELECTROSTATIC DEPOSITION OF ALKYL-GRAFTED POLY(ACRYLATES)-SURFACTANT COMPLEXES

Ioana Cătălina Gîfu*, Alina Iovescu, Monica Elisabeta Maxim, Elena-Livia Simion, Ludmila Aricov,

Dan-Florin Anghel “Ilie Murgulescu” Institute of Physical Chemistry, Romanian Academy, 202 Spl. Independentei, 060021 Bucharest,

Romania, Tel/Fax: ++40213121147 *E-mail: [email protected]


Wettability is an important property of solid surfaces, which is affected by their chemical composition

and geometrical microstructure [1]. Hydrophobic surfaces have low wettability and this make them useful for analytical, environmental and medical applications, antiseptic nanostructures, and many others.

The present study demonstrates that hydrophobic glass can be obtained by using poly(electrolyte) multilayer films with a hills and valleys geometry. Self-assembled multilayered films were prepared by alternate deposition of poly(diallyldimethylammonium chloride) (PDADMAC) and hydrophobically modified poly(acrylate) (HMPA) in the presence and absence of surfactants and inorganic salt. The influence of the number of adsorbed layer, concentration of salt and the alkyl chain lengths grafted on the polymer and of surfactant was examined. Contact angle (CA) measurements reveal that films obtained with poly(acrylates)-surfactant complexes are better water repellants than those without surfactant. For example, in Figure 1 are presented the AFM images and CA profiles for polyelectrolyte films and for polyelectrolyte-surfactant complexes. Salt addition into the dipping solutions gives rise to thinner films and less-coarse surfaces as witnessed by scanning electron microscopy (SEM) and atomic force microscopy (AFM), data that will revealed during the presentation.

Figure 1. 2-dimensional topographic AFM images of: (a) (PAC18Na/PDADMAC) (RMS=1,42 nm), (b) (PAC18Na-C18TAB/PDADMAC) (RMS=14.39 nm) for 1 bilayer .

Acknowledgements This paper has been financially sustained by the Romanian Academy within the research program „Colloids and dispersed systems” of the „Ilie Murgulescu” Institute of Physical Chemistry. The authors gratefully acknowledge the support of EU (ERDF) and Romanian Government allowing for acquisition of the research infrastructure under POS-CCE O2.2.1 project INFRANANOCHEM, No. 19/2009.03.01 and of PN-II-ID-PCE-2011-3-0916 grant.

References [1] T. Bharathidasan, V. Kumar , M.S. Bobji , R.P.S. Chakradhar, B.J. Basu, Appl. Surf. Sci., 2014, 314,

241-250.



OC 3. POLYION-DRIVEN SELF-ASSEMBLY OF SPHERICAL VIRUS-LIKE NANOPARTICLES INVESTIGATED BY MOLECULAR DYNAMICS SIMULATIONS

Daniel G. Angelescu*

Institute of Physical Chemistry “Ilie Murgulescu”, Romanian Academy, Splaiul Independentei 202, Bucharest, Romania



As the simplest definition, a virus consists of a protein capsid surrounding an encapsulated nucleic acid or another cargo molecule, such as a synthetic polymer or an inorganic nanoparticle. The virus capsids are highly dynamic structures that self-assemble from numerous copies of one or slightly different proteic units, called capsomers, into varying geometries and sizes. They are spherical-like or cylindrical aggregates whose sizes are much smaller than the linear size of the virus genome. Most of the former structures possess icosahedral symmetry and therefore the capsids are limited by the geometric constraint that the capsomers to be arranged into a regular polyhedron. The encapsulation mechanism depends pronouncedly on the genome nature: i) viruses with flexible single stranded genome (ssRNA) assemble spontaneously from free capsomers and genome; ii) the much more stiffened double stranded genome (dsDNA) is loaded in a pre-formed empty capsid.

Molecular dynamic investigations of a coarse-grain model describing the self-assembly of a virus-like nanoparticle with icosahedral symmetry in the presence of an oppositely charged linear and flexible polyion will be presented. Depending on the polyion length and the strength of capsomer-capsomer interaction, the simulations predict complex morphologies, including icosahedral capsules or disordered assemblages enclosing either completely or partially the polyion. The assembly kinetics is characterized in terms of the time-dependent cluster size and polyion extension and the structural properties of the resulting virus-like nanoparticle are quantified by means of the symmetry and radial distribution of the polyion.

a)

b)

c) Figure. a) Model system of a single triangular capsomer and b) snapshot and c) cut-section revealing the

assembly of 20 capsomers around a linear flexible polyion consisting of 100 segments. Spheres with specific interactions are colored as follows: i) capsomer: red – soft repulsive beads, white and green –

attractive beads, light blue – positively charged beads and ii) polyion: yellow – negatively charged beads Acknowledgements The support of Romanian National Authority for Scientific Research, CNCS–UEFISCDI, through the project number PN-II-RU-TE-2012-3-0036, is acknowledged. References [1] R. Zhang, P. Linse, J. Chem. Phys. 2014, 140, 244903. [2] J.D. Perlmutter, C. Qiao, M.F. Hagan, eLife 2013, 2, e00632.



OC 4. HYDROGEN BONDED COMPLEXES BETWEEN POLY(N-VINYLCAPROLACTAM) AND A MALEIC ACID COPOLYMER – INTERACTION STUDY AND APPLICATION IN DRUG

DELIVERY

Irina Popescu* “Petru Poni” Institute of Macromolecular Chemistry, Aleea Grigore Ghica Voda, 700487 Iasi, Romania



The poly(N-vinylcaprolactam) / poly(maleic acid-alt-styrene) (PVCL / MAc-St) system was

investigated in dilute aqueous solution, when hydrogen-bonding interactions between COOH groups of MAc-St and C=O groups of PVCL, together with hydrophobic interactions are involved in the formation of the complex. The influence of the pH, the added salt and the ratio between the components on the precipitation of the complex was study. The critical pH value increase with the addition of inorganic salt from 2.85 in pure water to 4.95 in 0.01 M NaCl. An unexpected behavior was the presence of two maxima when the optical density of the mixed solutions were plotted against the mixing ratio (Figure 1). The same system was study in solution, at pH higher than the critical pH, by potentiometry, viscometry and fluorescence of pyrene probe in order to acquire further information about the interaction between the polymers. The phase transition of the thermosensitive PVCL in the presence of MAc-ST was also studied (Figure 2). This influence have been shown to depend in large extend by the pH.

In order to study the potential use of this system in controlled drug delivery, spherical beads were prepared by complexation of MAc-St and PVCL in acidic medium (Figure 3). The beads were loaded with metoclopramide as a model drug. The pH and the ionic strength of the medium have been shown to influence the drug release profile (Figure 4) by controlling the dissolution of the complex.

Figure 1. The effect of the pH on the optical density of MAc-St / PVCL equimolecular mixture in pure water and at the addition of salt

Figure 2. The influence of the MAc-St addition on the cloud point of PVCL aqueous solution at pH = 4.5 and 3.5

Figure 3. SEM image of MAc-St/PVCL beads Figure 4. Drug release profiles from MAc-

St/PVCL beads in two buffer solutions Acknowledgements This work was supported by a grant of the Romanian Ministry of Education, CNCS – UEFISCDI, project PN-RU-TE-2014-4-0437



OC 5. TRANSIENT POLYMER NETWORKS FORMED IN SOLVENT. DOSY NMR AND RHEOLOGICAL INVESTIGATIONS

Monika Gosecka*, Mateusz Gosecki, Slawomir Kazmierski

Centre of Molecular and Macromolecular Studies of Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz, Poland


The presence of numerous 1,2-diol functional groups in the peripheral area of the hyperbranched

polyglycidol (HbPGL) macromolecules enabled to apply this polymer for the formation of hydrogel systems in the reaction with small molecular boronic crosslinking agents, i.e., benzene-1,4-boronic diacid and B(OH)4

Ө ions. The reversible character of this reaction assures that obtained materials exhibit self-healing properties [1]. Due to the fact that crosslinking reaction is sensitive to pH [2], it was essential to elaborate the optimal conditions for hydrogel formation, including the concentration of crosslinker, which significantly influences the hydrogel formation.

DOSY NMR experiments carried out for semi-diluted solutions lead to the significant reduction of the required amount of polymer necessary for elaboration of pH and crosslinker/polymer ratio for the formation of the hydrogel of desired characteristics. These results were verified with rheological characteristics of samples prepared at analogical conditions, though applying more concentrated polymer solutions. Generally, when diffusion coefficient of polymer objects was above 6.60·10-11 m2/s (the average molecular volume of objects below 75.0 nm3), the gel formation was not possible. It is evident that the higher the reduction of diffusion coefficient of macromolecules is, the higher crosslinking density within hydrogel is observerd on the basis of the increase in the maximum of storage modulus plateau. The maximum of storage modulus at high frequencies is gradually increasing with the concentration of boronic crosslinker (Figure 1), as the number of covalent junctions per one macromolecule is rising.

Figure 1. G'max (ω) of hydrogels versus diffusion coefficient of polymer objects present in solution

containing polymer with crosslinker at various pH and molar ratio of diol functional groups per one boronic acid site.

Generally, DOSY NMR and rheological investigations revealed that benzene-1,4-boronic diacid is

more efficient agent in HbPGL crosslinking than inorganic B(OH)4Ө ions. Moreover, the combination o NMR

and DOSY NMR results was helpful to state that intramolecular crosslinking within a single HbPGL macromolecule is not a favourable process. References [1] E.B. Stukalin, L.-H. Cai, N.A. Kumar, L. Leibler and M. Rubinstein, Macromolecules 2013, 46, 7525-

7541 [2] M. van Duin, J.A. Peters, A.P.G. Boom, H. van Bekkum, Tetrahedron 1984, 40, 2901-2911



OC 6. FLUORESCENCE INVESTIGATION OF HYDROPHOBICALLY MODIFIED POLYACRYLATES IN AQUEOUS SOLUTION AND IN THE PRESENCE OF SURFACTANTS

Ludmila Aricov*, Adriana Băran, Elena Livia Simion, Ioana Cătălina Gîfu, Dan-Florin Anghel

“Ilie Murgulescu” Institute of Physical Chemistry, Romanian Academy, Spl. Independentei 202, 060021 Bucharest, Romania



Water-soluble hydrophobically modified sodium polyacrylates (NaPACn) were synthesized by

grafting the poly (acrylic acid) (PAA) with 3 % (mol) C10 and C18 linear alkyl side-chains. The photopshysical properties of the NaPACn and their mixtures with surfactants were investigated by fluorescence spectroscopy, using pyrene as a probe. Cationic, anionic and nonionic surfactants with the same alkyl chain length (i.e., C12) were employed. The steady-state fluorescence results proved that the sodium polyacrylate (NaPA) does not have hydrophobic microdomains to accommodate pyrene inside. Instead, the NaPACns unveiled intracoil aggregates at a certain polymer concentration which decreases with the alkyl chain length. For aqueous grafted polyacrylate solutions, the dynamic fluorescence proved the existence of both intra- and intercoil aggregates, because the pyrene lifetimes have various values in the different microdomains (Figure 1).

The association of unmodified and modified polymers with surfactants are strongly dependent on the presence of hydrophobic microdomains and the surfactant nature. Therefore, the hydrophobic interactions play an important role, especially for the NaPAC18 – surfactant systems due to the low polarity of the polymer. It was also observed that the cationic surfactant strongly interact with the polymers, while the anionic one hardly did. The nonionic surfactant had an intermediate association behavior. For the mixed systems, the lifetimes of the probe were not much affected by the cationic and nonionic surfactants.

Figure 1. The modification of fluorescence lifetimes with polymer concentration

Acknowledgements The research has been financially supported by the Romanian Academy within the research programme „ Functional Complex Colloids” of the „Ilie Murgulescu” Institute of Physical Chemistry. The support of EU (ERDF) and Romanian Government (POS-CCE O2.2.1 project INFRANANOCHEM, No. 19/2009.03.01) and of (UEFISCDI) (Project PN-II-ID-PCE-2011-3-0916, Contract No. 177/2011) is gratefully acknowledged.



OC 7. INFLUENCE OF THE C12 SURFACTANTS CONCENTRATION ON THE MORPHOLOGY OF SPRAY PYROLYSIS DEPOSITED ZnO

Maria Covei*, Cristina Bogatu, Dana Perniu, Anca Duta

"Transilvania" University of Brasov, Bd. Eroilor, no. 39, 500036, Romania *E-mail: [email protected]

Surfactants are materials that behave differently in solutions above and below a certain

concentration, named the critical micelle concentration (CMC). Below this value, surfactants mainly stick to the surface/interface or can be randomly distributed into the solvent, whereas above it, they form aggregates (micelles) in the colloidal size range. Given the importance of the CMC, its value is well-known for the most largely-used surfactants in aqueous solution, at room temperature. However, surfactants’ CMC in disperse systems that also include electrolytes and a combination of water–organic solvent will lead to completely different behavior, both in terms of CMC and of the micelles shape.

Spray pyrolysis deposition (SPD) is a thin film chemical deposition method that uses a precursor solution which is dispersed through an atomizer by a carrier gas under pressure. The atomized droplets are carried to a heated substrate, where the solvent evaporates. Thin films form as a result of the cation precursor adsorption on the substrate, followed by reaction (e.g. with the oxygen in air), while the volatile by-products are removed by evaporation. Surfactants will therefore have a multiple effect: on the droplets size (by changing the surface pressure), in the precursor system by interacting with the precursor cation and further on, during film nucleation and growth, by modifying the kinetics of the cations-surfactant complex. Although organometallic precursors are mentioned, sustainable and low cost SPD processes use inorganic metallic salts as thin film precursors.

The paper discusses the influence of the precursor system composition on the CMC of three surfactants, with linear C12 tail, in a water-ethanol mixture of different ratios (2:1, 1:1 and 1:2) for the anionic sodium dodecyl sulfate (SDS), the cationic dodecyl trimethyl ammonium bromide (DTAB) and the non-ionic dodecanol (DD). A precursor systems is investigated, containing zinc acetate, usually selected to obtain ZnO through SPD. Moreover, acetylacetone (AcAc) is added into the system to lower the solution viscosity. Complex-type structures (Zn-AcAc, Zn-surfactant and/or AcAc-Zn-surfactant) are developed, both in the bulk precursor system and in the atomized drops.

The critical micelle concentration was experimentally measured using conductometry. The three surfactants were further added in concentrations higher and, respectively lower than their CMC and the surfactant type and concentration was correlated with the morphology and wetting properties of the SPD deposited films. It was found that the interactions between the surfactants, the zinc precursor and acetyl acetone are strongly dependent on the surfactant head: there is a much stronger attraction between Zn-AcAc complex structures and SDS, compared to those involving DTAB or DD, which takes place through a double layer. This affects the size, stability and distribution of the larger molecules (both pre- and post-micelles) in the precursor solution and sprayed droplets, which in turn affects the growth kinetics and/or mechanisms, allowing to tailor the surface morphology, as Figure 1 shows.

(a) (b) (c)

Figure 1. Micrographs of ZnO thin film obtained using: (a) SDS at concentrations lower than CMC; (b) DTAB at concentrations lower than CMC; (c) DTAB at concentrations higher than CMC.

Acknowledgements This work was performed using financial support provided by the Project:M-ERA-NET „Watersafe” 117847.



OC 8. ALGINATE / SPINEL FERRITE COMPOSITE AS MAGNETIC ADSORBENT FOR ENVIRONMENTAL APPLICATIONS

Andra-Cristina Humelnicu*, Corneliu Cojocaru, Petrisor Samoila, Petronela Pascariu Dorneanu,

Valeria Harabagiu "Petru Poni" Institute of Macromolecular Chemistry, Grigore Ghica Voda Aley, 41A, 700487 Iasi, Romania


Dedicated to the 150th anniversary of Romanian Academy

Adsorption is an efficient purification technique for the removal of dyes from wastewaters [1]. However, the separation of the spent adsorbents still remains a drawback. In this regard, the magnetic separation has recently attracted attention as a feasible alternative for common separation methods.

The objective of this work was to develop efficient alginate / spinel ferrite composites as magnetic adsorbents for the removal of cationic dyes from aqueous solutions. Pure NiFe2O4 was prepared by the sol-gel auto-combustion method [2] using citric acid as a fuel agent. The crystal structure and surface morphology of the inorganic material (NiFe2O4) were characterized by infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD) and transmission electron microscopy (TEM). The composite materials were prepared from alginate aqueous solutions (2-3% w/w) and diluted ferrofluid obtained by NiFe2O4 dispersion under ultrasonication in water. The resulted alginate/NiFe2O4 solutions were cast on Petri dishes following the solvent evaporation. The obtained membranes were subsequently cross-linked in CaCl2 aqueous solutions (0.05 – 0.15M). Next, membranes were cut and grinded to obtain composite powders with average particle size of about 500 µm. The content of inorganic magnetic support (NiFe2O4) in composite varied into the range of 15-25% w/w. The alginate materials were characterized by infrared spectroscopy (Fig.1). The produced composite adsorbents (Ca-alginate/ NiFe2O4) were applied for the removal of the cationic dye (Rhodamine-6G) from aqueous solutions containing 50 mg/L initial dye concentration. The experiments were carried out according to a full factorial design, and the adsorption process was monitored by UV-VIS method (526 nm). Consequently, a multivariate regression model was developed to predict the adsorption capacity (q, mg/g) of materials as a function of controllable factors (i.e. alginate concentration, amount of NiFe2O4 and CaCl2 concentration). The developed mathematical model in terms of actual variables is given as follows:

1 2 3 1 2 1 3 2 3ˆ 8.3 4.51 0.18 41.7 0.046 25.1 1.44q C C C C C C C C C (1)

subject to: 2.0≤(C1 :Alginate)≤3.0 % w/w; 15≤(C2 : NiFe2O4)≤25 % w/w; 0.05≤(C3 :CaCl2)≤ 0.15 M The response surface plot showing the effect of factors on the material’s response (i.e. adsorption

capacity) is depicted in Fig.2. The model-based optimization enabled to find the optimal composition of the material (i.e., C1=3% w/w; C2=15% w/w and C3=0.05M) that ensured the highest adsorption capacity of q = 19.7 mg/g.

Figure 1. FTIR spectra of alginate-based materials.

Figure 2. Response surface plot: q vs. (C1 and C3)

Acknowledgements This work was supported by a grant of the Romanian National Authority for Scientific Research and Innovation, CNCS – UEFISCDI, project number PN-II-RU-TE-2014-4-1266. References [1] E.N. El Qada, S.J. Allen, G.M. Walker, Chem. Eng. J. 2006, 124, 103-110. [2] P. Samoila, C. Cojocaru, I. Cretescu, C.D. Stan, V. Nica, L. Sacarescu, V. Harabagiu, J.Nanomater.,

2015, ID 713802, 1-13.



OC 9. BORAX COMPLEXES STARTING FROM ANIONIC SURFACTANT IN ASSOCIATION WITH UNLABELED OR FLUORESCENTLY LABELED POLY(ACRYLIC ACID)S

Elena Livia Simion*, Gabriela Stîngă, Adriana Băran, Ludmila Aricov, Ioana Cătălina Gîfu, Dan

Florin Anghel Department of Colloids, “Ilie Murgulescu” Institute of Physical Chemistry, Romanian Academy, 202 Spl.

Independentei, 060021 Bucharest, Romania *E-mail: [email protected]


Interactions between polymers and surfactants is a topic of great interest, due to their use as colloidal

systems stabilizers, rheology modifiers, emulsifiers or flocculating agents in products such as cosmetics, food, medicines, detergents or paints. Inorganic salts can moderate the electrostatic effect influencing the surfactant-polymer association. On the other hand, borax has found applications in a large diversity of fields including detergents, soaps, medicine, optoelectronics, hydraulic fluids for oil recovery, metallurgy, ceramics and glass, insecticides, etc. In this study we evaluated borax’s effect upon sodium dodecyl sulfate (SDS)-poly(acrylic acid) (PAA) complexes. Comparison was made by using both unmodified and fluorescently modified polymers. Also, the effect of sodium chloride versus borax on the polymer-surfactant complexes was followed. To this end, a poly(acrylic acid) with molecular weight of 25000 was grafted with 2.4 % 1-naphthylmethylamine (PAA25Np42).

Surface tension, and conductivity measurements reveled that both naphthyl tag and borax reinforce the interaction between SDS and polymer. The photophysical data (polarity index, excimer formation and lifetimes) obtained from steady-state and time-resolved fluorescence measurements gave insight on the nanostructures formed between the weak polyelectrolyte and the anionic surfactant. Figure 1 shows the ratio of monomer to excimer intensity (IE/IM) for the grafted polymer which can be used as a measure of the self-association of the aromatic groups, as well as a conformational index of the polymer chain.

10-3

10-2

10-1

0.32

0.36

0.40

0.44

I E/I

M

[SDS], M

without salt

5x10-3

M NaCl

1.3x10-5

M borax

5x10-3

M borax

Figure 1. Variation of IE/IM of PAA25Np42 versus SDS concentration without salt, in presence of 1.3x10-5

M or 5x10-3 M borax, as well as 5x10-3 M NaCl. Acknowledgement This paper was carried out within the research program Colloids and Dispersed Systems of the Ilie Murgulescu Institute of Physical Chemistry, financed by the Roumanian Academy. The authors gratefully acknowledge the support of the EU (ERDF) and Roumanian Government allowing the acquisition of research infrastructure under POSCCE O 2.2.1 project INFRANANOCHEM – Nr. 19/01.03.2009 and of The Executive Agency for Higher Education, Research, Development and Innovation Funding (UEFISCDI), Project PN-II-ID-PCE-2011-3-0916, Contract No. 177/2011.



OC 10. OSMOLYTES EFFECT ON THE STRUCTURE AND KINETICS OF CANDIDA RUGOSA LIPASE ENCAPSULATED IN REVERSE MICELLES

Anca Ruxandra Leonties1, Gabriela Stângă1, Adina Răducan2, Dan-Florin Anghel1

1”Ilie Murgulescu” Institute of Physical Chemistry, Spl. Independenței 202, Post Office 12, P.O. Box 194 060021, Bucharest, Romania

2 Faculty of Chemistry, University of Bucharest, Bd. Elisabeta 4-12, 030018, Bucharest, Romania *E-mail: [email protected]


Nowadays, the enzyme stability is an important task of research. Naturally occurring osmolytes can

be used as proteins stabilizers. This study is focused on the effect of trehalose, myo-inositol and phytic acid on the structural stability and activity of Candida rugosa lipase. Spectroscopic insights were revealed on the structure of lipase using UV-Vis, steady-state fluorescence and circular dichroism. Also, the kinetics of lipase-catalyzed hydrolysis of olive oil in reverse micellar media in the presence of osmolytes was studied. The fluorescence results show that the structure of lipase is modified by osmolytes in aqueous and micellar media. Circular dichroic spectra indicated that the protein undergoes some conformational changes upon interacting with these osmolytes (Figure 1). The kinetics of the enzyme encapsulated in reverse micelles in the presence of trehalose, myo-inositol and phytic acid differ from those when none of the additives were present. Lipase exhibits “superactivity” in reverse micelles when trehalose and myo-inositol are present and the activity is significantly lowered by the phytic acid. Results of this study could give further insights about the enzyme stabilization mechanism.

200 210 220 230 240 250

-30

-20

-10

0

10

((

md

eg

)

(nm)

Figure 1. Circular dichroic spectra of aqueous lipase in the presence of trehalose (★), myo-inositol (▲),

water (■) and phytic acid (●)

Acknowledgements This study was carried out within the research programme „Complex Functional

Colloids” of the „Ilie Murgulescu” Institute of Physical Chemistry, financed by the Romanian Academy. The

authors gratefully acknowledge the support of EU (ERDF) and Romanian Government allowing for

acquisition of research infrastructure under POS-CCE O 2.2.1 project INFRANANOCHEM, No.

19/2009.03.01, and of PN-II-ID-PCE-2011-3-0916, No. 177/2011 project.



OC 11. ANTIVIRAL EFFECT AGAINST HEPATITIS B VIRUS OF NANOCOMPOSITES SELF-ASSEMBLIES OF PLASMONIC GOLD/LAYERED DOUBLE HYDROXIDES

Gabriela Carja1*, Elena Florentina Grosu1, Catalina Petrareanu2, Norica Nichita2

1Department of Chemical Engineering, Faculty of Chemical Engineering and Environmental Protection, Technical University “Gh. Asachi” of Iasi, Bd. Mangeron No. 71, Iasi 700554, Romania.

2Department of Viral Glycoproteins, Institute of Biochemistry of the Romanian Academy, Splaiul Independentei 296, Bucharest 060031, Romania


The design of complex nanocomposites engineered to interact with cells and to specifically act

against hepatitis B virus (HBV) is a challenging approach in the conditions that the current therapies against HBV infections have limited efficacy and serious side effects. Herein, the antiviral effect of the self-assemblies of plasmonic gold and layered double hydroxides (AuNPs/LDHs) is demonstrated, for the first time, using HBV as a model virus and the hepatoma-derived HepG2.2.215 cells supporting viral replication, assembly and secretion of infectious virions and subviral particles [1].

AuNPs/LDHs were obtained by a simple procedure in which small AuNPs (~ 3.5 nm) were directly obtained and organized on the surface of larger nanoparticles (150 nm) of LDHs by exploiting the capability of the specific compositions of MgLDH, ZnLDH and MgFeLDH to manifest their “structural memory” in the aqueous solution of Au(O2CCH3)3. The self-assembly approach of AuNPs and LDHs was studied by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (PXRD) and UV-Vis analysis (UV-Vis). All AuNPs/LDHs reduced the amount of viral and subviral particles released from treated cells by up to 80% and exhibited good cytocompatibility. AuNPs/MgFeLDH showed the highest antiviral HBV response with more than 90% inhibition of HBV secretion for the whole concentration range. With these antiviral properties and low cytotoxicity plasmonic gold/LDHs nanocomposites hold great potential to be tailored as novel efficient therapeutics for the treatment of hepatitis B.

Figure 1. HBV antiviral activity of AuNPs/ZnAlLDH. Acknowledgements The authors gratefully acknowledge the financial support from the Romanian National Authority for Scientific Research, CNCS-UEFISCDI; project number PN-II-IDPCE 75/2013. References [1] G. Carja, E.F. Grosu, C. Petrarean, N. Nichita, NanoResearch, 2015, 8/11, 3512-3523.



OC 12. DESIGNING AND CHARACTERIZATION OF NOVEL IPN COMPOSITE CRYOGELS BASED ON POLY(N,N-DIMETHYLAMINOETHYL METHACRYLATE) AND

POLY(ACRYLAMIDE)

Ecaterina Stela Dragan*, Ana Irina Cocarta “Petru Poni” Institute of Macromolecular Chemistry, Aleea Grigore Ghica Voda 41A, 700487 Iasi, Romania



Living systems respond to external stimuli by adapting themselves to changing conditions. Smart

polymers, defined as polymers that undergo reversible changes in response to small external changes in the environmental conditions, such as temperature, pH, magnetic or electric field, solvent composition, ionic strength and so on, have been designed to mimic this behavior. Smart polymers have various applications in the biomedical field as delivery systems of therapeutic agents, tissue engineering scaffolds, cell culture supports, bioseparation devices, sensors or actuators systems. Interpenetrating polymer networks (IPN) have been widely used last decade to generate more sophisticated and more efficient drug delivery systems. Temperature and/or pH responsive IPN composite hydrogels based mainly on polysaccharides and biocompatible synthetic polymers have attracted much of attention [1-6].

The aim of this study was to prepare novel IPN hydrogels by a sequential strategy consisting of the preparation first of a poly(N,N-dimethylaminoethyl methacrylate) (PDMAEM) cationic network, and then a poly(acrylamide) (PAAm) network by using N,N’- methylenebisacrylamide as cross-linker. Both networks were macroporous and generated by cryogelation technique. The presence of PDMAEM endows the cryogels with sensitivity at numerous external stimuli such as: pH, temperature, ionic strength, electric field, among which the first three will be discussed. IPN cryogels were characterized by scanning electron microscopy, and water uptake as a function of pH, temperature and ionic strength. The release of diclofenac sodium (DS) from the macroporous IPN composite cryogels was evaluated as a function of pH and temperature. It was found that at pH 7.4 the IPN cryogels present the highest percentage of DS release. The release mechanism of DS has been also evaluated. Acknowledgements This work was supported by a grant of the Romanian National Authority for Scientific Research, CNCSIS – UEFISCDI, project number PN-II-ID-PCE-2011-3-0300. References [1] C.W. Peak, J.J. Wilker, G. Schmidt, Colloid Polym. Sci. 2013, 291, 2031. [2] E.S. Dragan, Chem. Eng. J. 2014, 243, 572. [3] N. Zhang, M. Liu, Y. Shen, J. Chen, L. Dai, C. Gao, J. Mater. Sci. 2011, 46, 1523. [4] Y. Liu, Y. Cui, J. Appl. Polym. Sci. 2011, 120, 3613. [5] E.S. Dragan, Pure Appl. Chem. 2014, 86, 1707. [6] E.S.Dragan, A.I. Cocarta, M. Gierszewska, Colloids Surf. B: Biointerfaces 2016, 139, 33-41.



OC 13. FLUORESCENTLY LABELED POLY(ACRYLIC ACID) IN CONFINED MICROENVIRONMENTS

Gabriela Stîngă*, Adriana Băran, Alina Iovescu, Elena Livia Simion, Ludmila Aricov,

Dan-Florin Anghel “Ilie Murgulescu” Institute of Physical Chemistry, Romanian Academy, 202 Spl. Independentei, 060021, Bucharest,

Romania *E-mail: [email protected]


Pyrene-based materials are of major interest to designing organic electronic devices such as

sensors, light emitting diodes, dye sensitized solar cells or to shed light on the structure of proteins, peptides, lipid membranes, etc [1-3]. Although there are many reports on the behavior of polymers in aqueous solutions without and with surfactant or in pure organic solvent, much less is known about their association in confined media like reverse micelles (RMs). This study reports on self-aggregation ability of pyrene labeled poly(acrylic acid)s with various graft content in sodium bis(2-ethylhexyl) sulfosuccinate RMs. The fluorescent response of label in water and in RMs is compared. The results obtained from UV-Vis, steady-state and time-resolved fluorescence show that the photophysical properties of the pyrene depend on the hydration degree, the concentration and the graft content of polymer. The emission data indicate that the crowded micellar media tune the formation of pyrene excimers (see Figure 1). New insights regarding the interactions and dynamics of the fluorescently labeled polymer in the nanoscopic micellar aqueous host are highlighted.

350 400 450 500 550 6000

7

14

Flu

ore

sc

en

ce

In

ten

sit

y,

[a.u

.]

Wavelength, [nm]

water

w0 = 5

w0 = 7

w0 = 10

w0 = 15

Figure 1. Emission spectra of pyrene labeled poly(acrylic acid) obtained in RMs and in water for excitation wavelength of 350 nm

Acknowledgements This study was carried out within the research programme „Complex Functional Colloids” of the „Ilie Murgulescu” Institute of Physical Chemistry, financed by the Romanian Academy. The authors gratefully acknowledge the support of EU (ERDF) and Romanian Government allowing for acquisition of research infrastructure under POS-CCE O 2.2.1 project INFRANANOCHEM, No. 19/2009.03.01, and of PN-II-ID-PCE-2011-3-0916, No. 177/2011 project. References [1] C. Suarez-Germa, L.M.S. Loura, M. Prieto, O. Domenech, J.M. Campanera, M.T. Montero, J. Hernandez-Borrell, J. Phys. Chem. B, 2013, 117, 6741−6748. [2] K.T. Wong, D.M. Bassani, NPG Asia Materials, 2014, 6, 1-10. [3] K. Kaushlendra, S.K. Asha, J. Phys. Chem. B, 2014, 118, 4951−4962.



OC 14. PHYSICALLY AND CHEMICALLY CROSS-LINKED CELLULOSE CRYOGELS

Diana Ciolacu1*, Cyrielle Rudaz2, Tatiana Budtova2 1“Petru Poni” Institute of Macromolecular Chemistry, Department of Physical Chemistry of Polymers,

11 41A Grigore Ghica Voda Alley, 700487, Iasi, Romania 2MINES ParisTech, PSL Research University, CEMEF - Centre de Mise en Forme des Matériaux,

CNRS UMR 7635, CS 10207 rue Claude Daunesse 06904 Sophia Antipolis, France *E-mail: [email protected]


Porous cellulose matrices were prepared via dissolution in 8wt%NaOH-water, physical gelation and

chemical cross-linking with epichlorohydrin (ECH), coagulation in water and lyophilisation. Gelation was either via physical (“aging” of cellulose solutions) or chemical (cross-linking with different amounts of ECH).Cellulose and cross-linker concentration were varied. A schematic presentation of the preparation steps is shown in Figure 1.

Figure 1. Schematic presentation of physically and chemically cross-linked cellulose cryogels The behavior of gels upon coagulation and the swelling of cryogels in water were analyzed. An

anomalous high swelling at cross-linker concentration around stoichiometric molar ratio with cellulose was observed: while physical gels contract during coagulation in water and become opaque, chemically cross-linked gels swell and become transparent. Cellulose cryogel morphology, crystallinity and density were studied. NMR, XRD and DSC showed that the crystallinity of chemically cross-linked cellulose is lower than that of physically cross-linked counterparts, and it decreases with the increase of ECH concentration in solution. The results obtained allowed suggesting a hypothesis explaining the difference in structure formation during cellulose physical and chemical gelation

Acknowledgements This work was supported by a grant of the Romanian National Authority for Scientific Research and Innovation, CNCS - UEFISCDI, project number PN-II-RU-TE-2014-4-0558. A part of this work was also financial supported by French National Agency for Research (ANR), “Nanocel” project ANR-09-HABISOL-010.

Cellulose-

8%NaOH-water

solution

Cellulose

cryogel

physical gelation

coagulation Cellulose

hydrogel

freeze-dryingCellulose

gel

chemical gelation

Cellulose-

8%NaOH-water

solution

Cellulose

cryogel

physical gelation


hydrogel


gel

Cellulose-

8%NaOH-water

solution

Cellulose

cryogel

physical gelation


hydrogel


gel

chemical gelation



OC 15. SORPTION/RELEASE OF IONIC COMPOUNDS IN/FROM POLY(ETHYLENEIMINE)/POLY(ACRYLIC ACID) MULTILAYER FILMS

Claudiu-Augustin Ghiorghiță*, Florin Bucatariu, Ecaterina Stela Drăgan

“Petru Poni” Institute of Macromolecular Chemistry, Grigore Ghica Voda Alley 41A, 700487, Iasi, Romania *E-mail: [email protected]


Layer-by-layer assembly is a versatile and eco-friendly method for coating substrates with

polyelectrolyte multilayer (PEM) thin films having controlled architecture and functionalities [1]. The PEMs, either attached to the underlying substrates or as free-standing films, have been used extensively as delivery systems for numerous bioactive compounds, such as drugs, proteins or genes [2-4]. Herein, we investigate the sorption and release of ionic compounds in/from multilayer films assembled using poly(ethyleneimine) (PEI) and poly(acrylic acid) (PAA). First, PEI/PAA multilayer films deposited onto Daisogel microparticles were used for the sorption and release of the anionic dye Congo Red (CR). The sorption of CR by the composite microparticles was investigated as a function of the number of PEI layers deposited and on the cross-linking method used (thermal or with pyromellitic dianhydride). Furthermore, the composite microparticles showed a pH responsive release behavior of the sorbed dye. Afterwards, it was demonstrated the possibility to obtain free-standing PAA/PEI multilayer films using a mixt pH and solvent detachment procedure (Figure 1). For this purpose, poly(diallyldimethyl ammonium chloride) (PDADMAC) was used as sacrificial layer.

Figure 1. Schematic representation for the deposition, cross-linking and detachment steps used to obtain

the free-standing PAA/PEI multilayer film.

The free-standing PAA/PEI multilayer film showed a good capacity to sorb diclofenac sodium (DS), while the release was also pH responsive. Acknowledgements This work was supported by a grant of the Romanian National Authority for Scientific Research, CNCS – UEFISCDI, project number PN-II-ID-PCE-2011-3-0300. References [1] K. Ariga, Y. Yamauchi, G. Rydzek, Q. Ji, Y. Yonamine, K.C.W. Wu, J.P. Hill, Chem. Lett. 2014, 43,

36-68. [2] Z. She, M.N. Antipina, J. Li, G.B. Sukhorukov, Biomacromolecules 2010, 11, 1241-1247. [3] F. Bucatariu, C.-A. Ghiorghita, E.S. Dragan, Colloids Surf. B: Biointerfaces 2015, 126, 224-231. [4] F. Bucatariu, C.-A. Ghiorghita, E.S. Dragan, High. Perform. Polym. 2015, 27, 563-570.



OC 16. NEW ASPECTS OF THE BINDING OF ETHOXYLATED NONIONIC SURFACTANTS TO SERUM ALBUMINS REVEALED BY SPECTROSCOPIC TECHNIQUES

Alina Iovescu*, Adriana Băran, Gabriela Stîngă, Anca Ruxandra Leonties, Monica Elisabeta Maxim,

Dan Florin Anghel Colloids Chemistry Laboratory, „Ilie Murgulescu” Institute of Physical Chemistry, Romanian Academy, Spl.

Independentei 202, Sector 6, 060021 Bucharest, Romania *E-mail: [email protected]


Hydrophobic attraction has been considered for long time ago the main, if not the solely force of interaction between the serum albumins and the nonionic surfactants [1,2]. Nowadays, more sensitive techniques may further enlighten these systems.

In this communication we report the binding behavior of various levels of ethoxylated nonionic surfactants to a fixed serum albumin concentration. Mono-disperse tetra- (C12E4), hexa- (C12E6) and octa-ethyleneglycol mono n-dodecyl ether (C12E8), and poly-disperse eicosa-ethyleneglycol mono n-tetradecyl ether (C14EO20) are respectively considered. The investigation is done by fluorescence and circular dichroism. Pyrene probe also reports on these aqueous mixtures, as an extrinsic fluorophore.

Circular dichroism data show that the content of protein α–helix increases in surfactant presence. Static fluorescence spectra allow constructing the binding isotherms of the homologous surfactants. The protein fluorescence quenches through a static mechanism and fluorescence lifetime determinations confirm it. New insights upon the mechanism of interaction are provided by the thermodynamic binding parameters in corroboration with the dichroic results. Beside hydrophobic attraction, hydrogen bonding appears as another driving force of the interaction between serum albumin and ethoxylated surfactants. The ethylene oxide (EO) moiety mediates the formation of new H bonds between the apt NH groups of protein, with novel α-helix construction, as sketched in Figure 1. The results reveal an optimum EO chain length for hydrogen bonding with the albumin. More details will be given during the presentation.

Figure 1. Additional α–helix development in the less ordered regions of serum albumin

Acknowledgements The study has been financed by the Romanian Academy (research programme „Functional Complex Colloids” of the „Ilie Murgulescu” Institute of Physical Chemistry). The authors acknowledge the support of EU (ERDF) and Romanian Government allowing for acquisition of the research infrastructure under POS-CCE O2.2.1, project INFRANANOCHEM, No. 19/2009.03.01 and the support from PN-II-ID-PCE-2011-3-0916 grant. References [1] N. Nishikido, T. Takahara, H. Kobayashi, M. Tanaka, Bull. Chem. Soc. Jpn. 1982, 55, 3085-3088. [2] H. Durchschlag, K.-J. Tiefenbach, R. Weber, B. Kuchenmüller, R. Jaenicke, Colloid Polym. Sci. 2000, 278, 312-320.



OC 17. THE INFLUENCE OF SEVERAL PARAMETERS UPON THE BEHAVIOR OF PYRENE LABELED POLY(ACRYLIC ACID) IN AOT REVERSE MICELLE AS REVEALED BY NRET

Monica Elisabeta Maxim1*, Gabriela Stîngă1, Alina Iovescu1, Dan Eduard Mihăiescu2,

Adriana Băran1, Anca Ruxandra Leonties1, Marieta Balcan1, Dan Florin Anghel1

1Colloids Chemistry Laboratory, “Ilie Murgulescu” Institute of Physical Chemistry, Romanian Academy, Spl. Independenţei 202, 060021 Bucharest, Romania

2Organic Chemistry Department, Faculty of Applied Chemistry and Materials Science, “Politehnica” University of Bucharest, 1–7 Polizu Street, 011061 Bucharest, Romania



The AOT/water/isooctane system was investigated by nonradiative energy transfer (NRET) between naphthalene (Np) dissolved in the organic solvent and pyrene grafted on poly(acrylic acid) (PAA150-Py32) solubilized in the reverse micelle. The phenomenon was strongly dependent on pH, hydration degree (w0), polyelectrolyte concentration and addition of salt.

The UV-Vis measurements revealed polymer solubilization in the micellar nanocage. Specific interfacial interactions that can be correlated with the presence of the polymer at the oil/water interface are confirmed by FTIR. DLS results showed that the average hydrodynamic diameter (dh) of the formed aggregates increases with w0. This confirms that the polar groups area of the surfactant increases with the water content due to the steric effect of the alkyl chains [1]. Addition of increasing amounts of salt at constant w0, entails the decrease of dh. The phenomenon is due to the thinning of the electrical double layer of micelle [2]. By steady-state fluorescence the photophysical parameters of PAA150-Py32 (i.e., the polarity index, I1/I3 and the polymer conformation index, IE/IM) at different pH values were determined. For w0= 5, 7 and 10, I1/I3 increased with pH. IE/IM had a different behavior at smaller hydration degree (5, 7) than at higher hydration degree (10, 15). For w0 = 5, 7, as the micellar pH increases, IE/IM decreases from a pH value close to the pKa of the polymer and at w0 = 10, 15 the pH had no obvious influence upon the excimers formation. The emission of Py strongly depends on pH and NRET occurs for all studied pH values (Figure 1a). An efficient energy transfer in systems of this type is indicative for a stable oil-water interface. With increasing the polyelectrolyte concentration, at constant w0, the efficiency of NRET increases (Figure 1b).

The acquired results shed more light upon the factors that affect the stability of micellar interface and allow useful industrial and biomedical applications.

300 325 350 375 400 425 450 475 500 525 5500

15000

30000

45000

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150000

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pH =3.6

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nsity (

cps)

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(a)

300 325 350 375 400 425 450 475 500 525 550

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1.8 x 10-4 M PAA150-Py32

2.6 x 10-4 M PAA150-Py32

Inte

nsity (

cp

s)

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(b)

Figure 1. NRET in the AOT/water/isooctane/PAA150-Py32/Np systems with: a) w0=10 at different pH

values; b) w0=7, at different polyelectrolyte concentrations. Acknowledgements: This paper has been financially supported by the Romanian Academy within the research programme „Functional Complex Colloids” of the „Ilie Murgulescu” Institute of Physical Chemistry. The authors gratefully acknowledge the support of EU (ERDF) and Romanian Government allowing for acquisition of the research infrastructure under POS-CCE O2.2.1 project INFRANANOCHEM, No. 19/2009.03.01 and the support from PN-II-ID-PCE-2011-3-0916 grant. The contribution of Dan Eduard Mihăiescu has been funded by the Sectoral Operational Programme Human Resources Development 2007-2013 of the Ministry of European Funds through the Financial Agreement POSDRU/159/1.5/S/132397. References [1] R. M. Lynden-Bell, S.C. Morris, J.D. Barrow, J.L. Finney, C. Harper, Water and Life: The unique

Properties of H2O, Ed. CRC Press Taylor & Francis Group, Boca Raton, U.S.A., 2010, p. 138. [2] H. Fathi, J.P.Kelly, V.R. Vasquez, O. A. Graeve, Langmuir 2012, 28, 9267-9274.



OC 18. THE INFLUENCE OF THE CULTURE MEDIUM COMPOSITION ON THE EXOPOLYSACCHARIDE BIOSYNTHESIS

Anca Roxana Petrovici*, Irina Rosca, Alina Nicolescu, Mariana Pinteala, Diana Ciolacu

1“Petru Poni” Institute of Macromolecular Chemistry, Centre of Advanced Research in Bionanoconjugates and Biopolymers Department, 41A Grigore Ghica-Voda Alley, 700487, Iasi, Romania



The trend of orientation towards biopolymers and to design innovative products has led to a global

resurgence of interdisciplinary research on bacterial exopolysaccharides (EPS). Lactic acid bacteria (LAB) are capable to biosynthesize EPS. The EPS biosynthesis is strongly related to the fermentations conditions like culture medium composition, aeration rate, fermentations time and temperature and agitations conditions. The fermentation process in different culture medium composition of the same LAB strain, maintaining all other fermentative parameters constantly, may lead to different EPS amounts and in some cases to different EPS types.

In our case, we selected, isolated and purified from 34 LAB strains different samples. These strains were tested on three different culture medium compositions in order to select LAB strains that are highly EPS producers. From these 34 LAB strains we selected five in order to be subjected to the fermentative process in static and dynamic conditions, at 33°C for 48 hours. At the end of the fermentative process, the samples were subjected to enzyme inactivation (at 100 °C for 15 minutes) in order to stop the LAB strains growth and the enzymes actions on the EPS structure, avoiding the enzymatic degradations of the EPZ biosynthesized in culture mediums [1]. After the inactivation, EPS were extracted and purified following a protocol established according to the literature [2-5]. Due to the distinctive physico-chemical characteristics, one representative LAB strain (PP15) was presented in detail. The amount of purified EPS produced by this strain was evaluated by gravimetric measurement. The molecular weight and polydispersity index were determined by gel permeation chromatography (GPC). Thermal properties of the EPS samples were established by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The supra-molecular structures of EPS have been identified by Fourier transform infrared (FT-IR) and 1H nuclear magnetic resonance (1H-NMR) spectroscopies. Acknowledgements This work was supported by a grant of the Romanian National Authority for Scientific Research and Innovation, CNCS – UEFISCDI, project number PN-II-RU-TE-2014-4-0558. References [1] K.W. Lee, J.Y. Park, H.R. Jeong, H.J. Heo, N.S. Han, J.H. Kim, Anaerobe 2012, 18, 96-102. [2] C.T. Liu, F.J. Chu, C.C. Chou, R.C. Yu, Mutation Research 2011, 721, 157–162. [3] A. Tayuan, G.W. Tannock, S. Rodtong, African J. Microbiol. Research 2011, 5(22), 3693-3701. [4] R. Bennama, M. Fernandez, V. Ladero, M.A. Alvarez, N. Rechidi-Sidhoum, A. Bensoltane, Eur. Food Res. Technol. 2012, 234, 119–125. [5] S. Palomba, S. Cavella, E. Torrieri, A. Piccolo, P. Mazzei, G. Blaiotta, V. Ventorino, O. Pepe, Appl.Environ. Microbiol. 2012, 78(8), 2737-2747.



OC 19. MACROPOROUS SEMI-IPN COMPOSITE HYDROGELS BASED ON POLY(N,N-DIMETHYLAMINOETHYL METHACRYLATE) AND STARCH

Diana Felicia Loghin*, Ecaterina Stela Drăgan

1“Petru Poni” Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41A, 700487 Iasi, Romania *E-mail: [email protected]


Considerable interest has been focused last years on the smart hydrogels due to the numerous

applications in controlled delivery of drugs and proteins and separation processes of small ionic species [1,2]. These gels can change their volume and/or shape in response to of the external stimuli, such as pH, temperature, ionic strength, solvent composition, electric or magnetic field, etc. The biocompatibility and biodegradability of these gels can be improved with biopolymers like polysaccharides, as components of the gel architecture [3.4].

Novel macroporous semi-interpenetrating polymer network (semi-IPN) composite hydrogels based on potato starch (PS) or anionically modified PS (PA) as polymers entrapped in a matrix of poly(N,N-dimethylaminoethyl methacrylate) (PDMAEM), prepared by ice-templating strategy, will be presented. The semi-IPN composite cryogels have been characterized by scanning electron microscopy and by swelling

behavior as a function of the polysaccharides nature. The influence of the polysaccharides content and

nature (PS or PA) on the response of the composite cryogels at various stimuli was thoroughly investigated (Figure 1).

0 10 20 30 40 50 60 70 800

5

10

15

20

25 PDMAEM5.10.PA1

PDMAEM5.10.PA1.5

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40

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60

70

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eq

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Figure 1. Equilibrium swelling ratio (SReq) as a function of temperature (left) and pH (right) for some

composite cryogels prepared with PA as entrapped polymer.

The potential of thus prepared composite cryogels for controlled delivery of drugs was also investigated. Acknowledgements This work was supported by a grant of the Romanian National Authority for Scientific Research, CNCSIS – UEFISCDI, project number PN-II-ID-PCE-2011-3-0300. References [1] S. Hajizadeh, H. Kirsebom, I. Y. Galaev, B. Mattiasson, J. Separation Sci. 2010, 33, 1752-1759. [2] E. S. Dragan, Chem. Eng. J. 2014, 243, 572-590. [4] E. S. Dragan, M. M. Perju, M. V. Dinu, Carbohydr. Polym. 2012, 88, 270-281. [5] E. S. Dragan, D. F. Apopei, Chem. Eng. J. 2011, 178, 252-263.



OC 20. AGGREGATION OF SOME HYDROPHOBICALLY MODIFIED POLYACRYLATES IN AQUEOUS SOLUTION

Adriana Băran*, Ludmila Aricov, Dan-Florin Anghel Colloid Chemistry Laboratory, “Ilie Murgulescu” Institute of Physical Chemistry, Romanian Academy,

202 Spl. Independentei, Post Office 12, P.O. Box 194, 060021 Bucharest, Romania *E-mail: [email protected]


Water-soluble associative polymers (APs) are a class of compounds with hydrophilic backbone

decorated with a few hydrophobic groups. In water, above a threshold concentration, the hydrophobic moieties undergo association and APs show peculiar properties such as spectacular increase of viscosity, gelation, drag reduction, and elasticity. They result from the reversible association of labels, and make APs distinguishable from regular polymers without associative groups. As a result, APs triggered applications in many fields for instance, personal care products, cosmetic, carriers for protein, DNA and drugs, waterborne paints, wastewater purification, enhanced oil recovery, etc. We are interested in these polymers because the specific behavior of hydrophobically modified sodium polyacrylates (NaPACn) is given by the interplay between the electrostatic repulsions of the carboxylate groups and the attractions of the hydrophobic grafts. In aqueous solution, the hydrophobic groups try to avoid the contact with water, and form intra- and inter-macromolecular aggregates. Strong associations are obtained by increasing the alkyl chain length, because the modified polymers are less soluble in water. In this study, we are interested to find out new information on the behavior of randomly modified polyacrylates with linear C10 – C18 alkyl chains, by means of viscometry, steady-state fluorescence and refractometry. It is found out that each NaPACn has a characteristic overlapping concentration (c* - demonstrated by viscometry), which lowers as the grafted chain is more hydrophobic. Above c*, the viscosity deviates from that of sodium polyacrylate (NaPA) and solutions of high viscosity are obtained. Steady-state fluorescence unveils intra-coil hydrophobic microdomains, whereas refractive index reveals the existence of both intra- and inter-coil aggregates. The complementarity and agreement between results obtained by different methods is presented Figure 1,

together with a schematic representation of intra- and inter-coil aggregates.

Figure 1. The complementarities between the methods, together with a schematic representation of intra- and intercoil aggregates.

Acknowledgements The research for this paper has been carried out within the Functional Complex Colloids Program of the “Ilie Murgulescu” Institute of Physical Chemistry, financed by the Romanian Academy. The authors gratefully acknowledge the support of the EU (ERDF) and Romanian Government allowing for acquisition of research infrastructure under POS-CCE O 2.2.1 project INFRANANOCHEM, No. 19/01.03.2009. This work is also supported by the PN-II-ID-PCE-2011-3-0916 Exploratory Research Project.

10-5

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3

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RI

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OC 21. WATER-IN-OIL MICROEMULSIONS OF DIESEL AND DIESEL-RAPESEED OIL AS

ALTERNATIVE FUELS. PHASE BEHAVIOR, INTERFACIAL TENSION, SOLUBILIZATION

AND STRUCTURAL INVESTIGATIONS

Marieta Balcan, Florentina-Cristina Mihăilescu, Monica Elisabeta Maxim, Ioana Catalina Gifu,

Dan-Florin Anghel* Colloid Chemistry Laboratory, ‘Ilie Murgulescu’ Institute of Physical Chemistry, Romanian Academy, Spl.

Independentei, No. 202, 060021, Bucharest, Romania E-mail: [email protected]; [email protected]


The study presents the results on water-in-oil (w/o) fuel microemulsions (FME) containing diesel

and/or diesel-rapeseed oil (RO) mixtures and water with or without electrolyte. The amphiphiles used to

prepare the FME were eco-friendly namely: the nonionic surfactants Brij 30 (B30), Igepal CO-520 (NPEO5)

and Tween 65 (T65), the anionic surfactant Synperonic A9C (Na) (SA9C), and the cosurfactant i-butanol

(B). The water solubilization capacity in FME was studied by using pseudo-ternary phase diagrams. The

one phase area for single nonionic surfactants follows the order: B30 > NPEO5 > T65. It increases for

mixtures of nonionic-anionic surfactant-cosurfactant, which allowed up to 10% wt. water solubilization

without phase separation. In the presence of electrolyte (sodium acetate, AcNa) the one phase area

decreases with the electrolyte concentration. In order to find the optimal formulation of the systems,

properties such as the phase behavior, oil/water interfacial tension (σow), solubilization of oil and water (SPo

and SPw) and structure of ME have been investigated for the Winsor (W)I ↔ WIII ↔WII system sequences

with the electrolyte concentration. In the WIII systems, σow is minimal, whereas SPo, SPw and the droplet

size are maximal. In all the investigated systems including those of WIV type, the particle size was in the

microemulsion domain (below 100 nm). The results aim to provide useful information in successfully

formulation and preservation of such ME as alternative fuels for diesel engines.

Acknowledgements The research for this paper has been carried out within the Functional Complex Colloids Program of the ‘Ilie Murgulescu’ Institute of Physical Chemistry, financed by the Romanian Academy. The authors gratefully acknowledge the support of the EU (ERDF) and Romanian Government allowing for acquisition of research infrastructure under POS-CCE O 2.2.1 project INFRANANOCHEM, No. 19/01.03.2009. This work is also supported by the PN-II-ID-PCE-2011-3-0916 Exploratory Research Project.




OC 22. BIOINSPIRED POLYTHIOPHENE-BASED POLYMERS IN HAIRY-ROD ARCHITECTURE: INFLUENCE OF GRAFTS LENGTH AND GRAFTING DENSITY ON THEIR

ELECTRO AND BIOACTIVITY

Anca-Dana Bendrea*, Luminita Cianga, Ioan Cianga

“Petru Poni” Institute of Macromolecular Chemistry, 41A Grigore Ghica Voda Alley, 700487, Iasi, ROMANIA *E-mail: [email protected]


The “complex simplicity” of Nature was always a model for chemists and materials scientists. Thus, shapes, properties and building strategies of biological macromolecules were followed for a plethora of synthetic analogues able of mimicking biological systems. The self-assembly (SA), a fundamental theme in Nature, is a key concept in “bottom-up” hierarchically organized structures and a powerful alternative to nanofabrication approaches. In this context and following our previous research interest in the polythiophene field, the present communication reports on new engineered rod-coil amphiphilic structures, in “hairy-rod” architecture, in which the complex attractive and repulsive interactions required for SA were already encoded in the basic units (Figure 1). By usefully combining the electroactivity and photophysical properties of oligo/polythiophene main chains with biocompatibility and water solubility of polyethylene glycol (PEG) side chains, using 2,5- dibrominated thiophene-containing macromonomers (M1 and M2) as versatile building “bricks”, various macromolecular structures were designed and synthesized. Due to peculiar architecture, side chains grafting density and side chains length are molecular parameters influencing morphology and physical properties. Carefully selecting polymers’ synthesis methods we succeeded to modify these parameters in a controlled manner, giving rise to freedom in properties tunability for a specific envisioned applications (tissue engineering [1,4], cell imaging [2,3]).

S

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S

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NiCl2

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Figure 1. The synthesis routes for the bioinspired polythiophene compounds

A lower grafting density of poly(ethylene glycol) (PEG) side chains on a polythiophene main chain

resulted in an improved electroactivity and electrostability[1,5].The influence of both parameters on cell viability[2,3] as well as on cellular adhesion and proliferation [1,4] and on electro-biocompatibility [1,5] of polymeric substrates was also demonstrated.

References

[1] S. Maione, G. Fabregat, L. J. del Valle, A.-D. Bendrea, L. Cianga, I. Cianga, F. Estrany, C. Aleman, J. Polym. Sci. B Polym. Phys. 2015, 53, 239-252. [2] L. Cianga, A.-D. Bendrea, N. Fifere, L. E. Nita, F. Doroftei, D. Ag, M. Seleci, S. Timur, I.Cianga, RSC Adv. 2014, 4, 56385–56405. [3] A.-D.Bendrea, L. Cianga, E.G. Hitruc, I. Titorencu, I. Cianga, Mat. Plastice. 2013, 50, 71-78. [4] A.-D. Bendrea, G. Fabregat, J. Torras, S. Maione, L. Cianga, Luis J. del Valle, I. Cianga, C. Aleman, J. Mater.Chem. B. 2013, 33, 4135-4145. [5] A.-D. Bendrea, G.Fabregat, L. Cianga, F. Estrany, Luis J. del Valle, I. Cianga, C. Aleman, Polym. Chem. 2013, 9, 2709-2723.



POSTER PRESENTATIONS


P1. WHEAT SEEDS AS MARKERS OF HEAVY METAL POLLUTION AND DECONTAMINATION OF TARNIŢA MINING AREA

Alina Elena Butnariu1*, Raluca Stefănescu2, Olga Pintilie3, Manuela Murariu4, Ion Bunia4,

Andriana Surleva5, Cătălina Ionica Ciobanu2, Carmen Iacoban6, and Maria Magdalena Zamfirache1 1Faculty of Biology, “Al. I. Cuza” University, 11 Carol I, Iasi-700506, Romania

2Faculty of Chemistry, “Al. I. Cuza” University, 11 Carol I, Iasi-700506, Romania 3 Faculty of Geography and Geology, “Al. I. Cuza” University, 11 Carol I, Iasi-700506, Romania

4Petru Poni Institute of Macromolecular Chemistry, 41A Gr. Ghica Voda Alley, Iasi-700487, Romania 5University of Chemical Technology and Metallurgy, Analytical Chemistry Department, Sofia, Bulgaria

6Forest Research and Management Institute, Research Station C-lung Moldovenesc Suceava, Romania *E-mail address: [email protected]

As a result of mining the metalliferous ores, metal pollution has become one of the most serious environmental problems in Tarnita area today [1]. The sterile dumps and soil around the closed barite mine of Tarnita, Suceava region, contain increased amounts of heavy metals such as copper, iron, lead and zinc, as well as arsenic. The seeds of wheat (Triticum aestivum L.) were used as indicator of toxicity for both sterile material and contaminated soils, since the metal-rich mining waste from Tarnita mine site have a negative effect on seed and seedling metabolism, which results in wheat week germination, growth inhibition, photosynthesis impairment, low water uptake and nitrate assimilation.

In our experiments, heavy metal contaminated materials were ultrasonic extracted with water in the ratio 1 g : 10 mL for at least 15 min, followed by centrifugation at 5000 rpm to obtain the clear supernatant. Lots of 50 wheat seeds were treated with 5 mL of toxic supernatant for 1 h, then let to germinate on double filter paper in 9-cm Petri dishes. Separately, the toxic metals concentrated in the supernatant was subjected to the sodium hydroxide-based precipitation. The resulted clear solution was neutralized with nitric acid solution and used in germination experiments or percolated through ion exchange resins. All these hydroxide-based or resin-treated decontaminated solutions were used in the biological investigations as well. The content of pollutants of all solutions was measured by ICP-OES or AAS. Since the contaminants were removed either by precipitation or ion exchange, the germination rate as well as the growth of the resulted plantlets increased significantly. Heavy metal accumulation in plant tissues resulted in the inhibition of most physiological processes [2]. Metals may penetrate the plants by absorption from soil solutions or by deposition of dust pollutants from the air, on the aerial parts of the plants. Some metabolic pathways leading to precipitation of heavy metals as metal sulfides, phosphates or carbonates are related to possible biotechnology application [3]. Acknowledgements Authors acknowledge to Partnership Project Metafore (Contract 107/2014) for financial support. References [1] D. Stumbea, Environ. Eng. Manag. J. 2010, 9, 1045-1051. [2] B.J. Alloway, Environ. Pollut. 2013, 22, 3-9. [3] P. Kotrba, T. Ruml, Czech. Chem. Communic. 2000, 65, 1205-1247.



P2. PARTICULATE MATTER AND GASEOUS POLLUTANTS VARIABILITY IN IASI URBAN AREA, NORTH-EASTERN ROMANIA

Alina-Giorgiana Galon (Negru)1, Romeo Iulian Olariu1,2, Cecilia Arsene1,2*

1”Alexandru Ioan Cuza” University of Iasi, Faculty of Chemistry, Department of Chemistry, 11 Carol I, 700506 Iasi, Romania

2”Alexandru Ioan Cuza” University of Iasi, Integrated Center of Environmental Science Studies in the North Eastern Region - CERNESIM, 11 Carol I, 700506 Iasi, Romania


Urban air pollution represents one of the greatest environmental problems facing humanity even

nowadays [1]. The most important air pollutants causing adverse effects on human health and environment include particulate matter (PM), ozone (O3), sulfur dioxide (SO2), nitrogen oxides (NOx=NO+NO2), carbon monoxide (CO), volatile organic compounds (VOCs) and heavy metals [2-3]. There is suggestion that increases in mortality and hospital admissions due to respiratory and cardiovascular diseases might be highly associated with air pollutants exposure [4]. Gaseous atmospheric species such as HNO3 (originated from NOx) and H2SO4 (derived from gas phase oxidation of SO2) are the most important precursors of nitrate and sulfate aerosols, comprising a significant fraction of the ambient air PM2.5 mass concentration [5]. Sunlight induced photochemical reactions of NOx and VOCs precursor gases represent an important pathway of the ground level O3 formation [6].

In the north-eastern Romania, Iasi region, reports on the variability of the previously mentioned air pollutants are very scarce. Information about the atmospheric burden of particulate matter and gaseous pollutants from the ambient air in Iasi urban area are reported in the present work. Ambient particulate matter samples were collected over a time period of 36-hour on aluminum filters using a 13 stages cascade Dekati Low-Pressure Impactor (DLPI) (0.0276-9.94 µm size range and 29.85 L min-1 flow rate). Simultaneously, samples have been collected on polycarbonate hydrophilic membranes (of 8.0 and 0.4 µm) and quartz filters appropriately disposed on a Stacked Filter Unit (SFU). For PM fractions the mass concentration has been gravimetrically determined. Gaseous pollutants like O3, CO, CO2, NOx and SO2

were measured using Ecotech analyzers. The meteorological data (temperature, relative humidity (RH), solar radiation, wind speed) were provided by a Weather Hawk GSM-240 station. Data analysis revealed that PM2.5 (particles of diameter <2.5 µm) and PM10 (particles of diameter <10 µm) fractions followed similar patterns. Chemical composition of the collected particles has been investigated for the water soluble ionic fraction. Completeness of the ionic balance has been used as a quality control step within data analysis process. The correlation between nitrate and sulfate mass fractions in PM2.5 and the NOx and SO2 precursor concentrations needs still to be addressed. From the entire set of measurements included in the database we expect, however, to extract meaningful information about the possible relationship between the measured variables and the process of new-particles formation in Iasi urban area. Acknowledgements The authors acknowledge the financial support provided by UEFISCDI within the PN-II-PCE-2011-3-0471 Project (EVOLUTION-AIR). CERNESIM Center is also gratefully acknowledged for the infrastructure used in this work. References [1] IPCC, 2013: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to

the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex, P.M. Midgley (eds.), Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1535 pp, doi:10.1017/CBO9781107415324; http://www.ipcc.ch/report/ar5/wg1/ (accessed March 01, 2016).

[2] WHO Air quality guidelines for particulate matter, ozone, nitrogen dioxide and sulphur dioxide, Global update 2005, Summary of risk assessment, WHO/SDE/PHE/OEH/06.02, Geneva, Switzerland, 2006 (accessed April 10, 2007).

[3] M. Kampa, E. Castanas, Environ. Poll. 2008, 151, 362-367. [4] B. Brunekreef, S.T. Holgate, The Lancet 2002, 360, 1233-1242. [5] S. Metzger, N. Mihalopoulos, J. Lelieveld, Atmos. Chem. Phys. 2006, 6, 2549-2567. [6] Y. Xie, B. Zhao, L. Zhang, R. Luo, Particuology. 2015, 20, 141-149.



P 3. THERMAL DEGRADATION STUDY OF BROMINATED FLAME RETARDANTS WITH EMPHASIS ON THE ESTIMATION OF HUMAN EXPOSURE THROUGH INDOOR DUST

INGESTION

Alin C. Dirtu1*, Mihai Dumitras1, Dan Maftei1, Anton Airinei2, Nita Tudorachi2, Dragos L. Isac2 1Department of Chemistry, “Alexandru Ioan Cuza” University of Iasi, Carol I Bvd, No. 11, 700506, Iasi, Romania

2“Petru Poni” Institute of Macromolecular Chemistry Iasi, Grigore GhicaVoda Al., No. 41A, 700487 Iasi, Romania *E-mail: [email protected]

Flame retardants (FRs) are materials that inhibit or resist the spread of fire that are added to polymers

which are used in consumer goods. The scientific literature in this field provides limited knowledge about the mechanisms via which these chemicals migrate into and behave in the indoor environment and finally influence the human exposure to such compounds [1]. In order to investigate their presence in matrices related to human exposure to these compounds, such as indoor dust samples or food items, the use of gas-chromatography (GC) coupled to mass spectrometry (MS) detection is needed [2]. However, given the relatively low volatility of some brominated FRs, higher elution temperatures are needed when applying conventional chromatographic techniques for their determination. Therefore, FRs might undergo thermal degradation generating errors in their analysis [2]. No systematic study on the thermal degradation of these compounds has been reported in the literature, while only a few papers report basic thermal degradation data for polybrominated diphenyl ethers (PBDEs) by HPLC under isothermal conditions and at low temperatures (below 100oC) [3] or by GC/ICP-MS [4].

The estimation of human exposure to FRs is based on reported levels for such compounds in several matrices like food or indoor dust [5]. By the use of thermogravimetric analysis combined with theoretical computations, it is possible to evaluate the most probable degradation products and investigate the thermal degradation mechanisms of selected brominated FRs. Further, some specific chromatographic techniques might be applied in order to reduce the thermal degradation of FRs due to instrumental analysis conditions. Throughout the following of this study we have estimated the behavior of decabrominated diphenyl ether (BDE 209), a FR which accounts for more than 90% of the total PBDEs reported from indoor dust samples from Eastern Romania [5].

Thermal degradation of BDE 209 has been investigated by simultaneous thermogravimetry (TG) and differential thermal analysis (DTA). Degradation experiments have been conducted under different atmospheres (nitrogen, helium and air) and with different heating rates. Information on the degradation products have been provided by temperature-resolved evolved gas analysis performed by on-line coupled FTIR and MS. For evaluation of the thermal behavior and stability of BDE 209, the relevant characteristics of the thermal degradation have been estimated (characteristic temperatures, thermal effects, degradation stages and the corresponding weight losses). In this respect, the degradation onset was found to occur at rather low temperatures, around 300oC, partially overlapping with melting and with little influence from experimental conditions. As expected, the temperature required for complete degradation depends on the heating rate, ranging from around 400 to 500oC for the (extreme) values of 2 K/min and 20 K/min, respectively.

The conclusions of the thermal degradation study, correlated with EGA-FTIR/MS data and molecular modeling results provide additional insight for interpreting GC experimental results and will serve as a basis for designing proper GC analytical methods for the selected FRs serving for a better estimation of the human exposure to such compounds. Acknowledgements Thermal degradation experiments were employed with an instrument (STA 449 F1 Jupiter, Netzsch) acquired by a grant supported by the ANCS, Ministry of Economy, Trade and Business Environment, through the National Program Capacities, Project No. 257/28.09.2010 (CERNESIM). This work was supported by a grant of the Romanian National Authority for Scientific Research and Innovation, CNCS-UEFISCDI, project number PN-II-RU-TE-2014-4-1010. References [1] A.C. Dirtu, A.C. Ionas, G. Malarvannan, A. Covaci, Transformation Products of Emerging Contaminants

in the Environment. John Wiley & Sons Ltd, England, 2014, p. 545. [2] A.C. Dirtu, M.A.E. Abdallah, A. Covaci, TRAC-Trend. Anal. Chem, 2013, 43, 189-203. [3] R. Ghanem, F.A. Delmani, J. An. Appl. Pyrolysis, 2012, 98, 79-85. [4] H. Tao, T. Nakazato, Bunseki Kagaku, 2009, 58 (5), 363-372. [5] A.C. Dirtu, N. Ali, N. Van den Eede, H. Neels, A. Covaci, Environ. Int. 2012, 49, 1-8.



P 4. NEW METHOD FOR THE PREPARATION OF CYCLODEXTRIN-COATED MAGNETIC NANOPARTICLES

Ana-Lacramioara Lungoci*, Adrian Fifere, Alexandru Rotaru, Mariana Pinteala

Centre of Advanced Research in Bionanoconjugates and Biopolymers, ‘‘Petru Poni’’ Institute of Macromolecular Chemistry, Aleea Grigore Ghica Voda 41A, 700487 Iasi, Romania



Functionalized magnetic nanoparticles are of great interest due to the multitude of personalized possibilities to be used in biomedical applications. Herein, we report on the two step preparation of cyclodextrin-functionalized silane-coated magnetic nanoparticles, synthesized by chemical coprecipitation of ferrous and ferric salts in basic medium, subsequently coated with 3-aminopropyl-trimethoxysilane, followed by the reaction between amino-surface groups and isothiocyanate of mono-substituted-β-cyclodextrin. The dynamic light scattering and transmission electron microscopy analyses of both the initial silane-coated magnetic nanoparticles and final cyclodextrin-modified ones revealed the uniformly formed spherical entities with the mean diameter of 20 nm. Supplementary information was added by infrared absorption spectra and X-ray photoelectron spectroscopy. Potential perspectives in biomedical field were addressed. Acknowledgement The authors are grateful to “Petru Poni” Institute of Macromolecular Chemistry for the financial support of this work via ERA Chairs Project (Grant Agreement No. 667387, Call Horizon 2020 WIDESPREAD 2-2014, PN-II-ID-PCCE-2011-2-0028, contract no. 4/2012)



P 5. STABILIZATION MECHANISMS OF TiO2 DISPERSIONS IN PHOTOCATALYTIC INKS

Cristina Bogatu*, Dana Perniu, Maria Covei, Anca Duta

Transilvania University of Brasov, Romania, R&D Centre: Renewable Energy Systems and Recycling, Eroilor 29, 50036, Romania

*E-mail: [email protected] Titanium dioxide inks are nowadays widely used as prepared or as thin films for applications involving

photocatalysis (in wastewaters treatment, air purification, self-cleaning fabrics etc.), sensors fabrication, solar cells, etc. The main issue related to their formulation is to reach a certain stability without significantly distorting the main application. The challenge in formulating stable dispersions is to prevent particles agglomeration/aggregation when dispersing into the continuous medium, phenomena driven by van der Waals attractions as predominant interactions at pH values close to the point of zero charge (PZC). The control of the particles synthesis and the dispersions formulation is required in terms of particle size and surface charge, dispersion concentration, continuous medium composition and pH; according to these, the type of stabilizers is then chosen.

Small sized TiO2 particles can be obtained using sol-gel method coupled with finely tuned ultra-sonication, (targeting the embedded energy, thus the power and duration of ultra-sound treatment); additionally, particles agglomeration followed by sedimentation can be prevented by addition optimized amount of suitable stabilizers in dispersion.

Surfactants are known as efficient stabilizers at concentration lower than the critical micelle concentration of the system, but also polymers, polyelectrolytes, capping agents can be used to improve stability. The stabilization occurs by steric/electro-steric mechanisms involving the adsorption of the stabilizer’s molecules on the particles, thus creating barriers against aggregation accompanied by repulsions between the stabilized particles.

In this study, Degussa P25 and ultrasound assisted TiO2 sol-gel (TiO2_US) were dispersed under ultrasonication in water, water-isopropanol, isopropanol (IPA) to get variously concentrated dispersions (0.1…10%). To balance particles attractions and achieve a good stability, five surfactants (anionic: SDS, cationic: DTAB and HTAB, non-ionic: PEG400 and Triton X-100), two polymers (polyvinylpirolidone-PVP and PAA) and one capping agent (TODA) were investigated. The stability was firstly qualitatively evaluated by visual observation, while transmittance spectra at preset moments were recorded as a quantitative stability measure (Fig. 1, Fig. 2) as sedimentation will increase the supernatant transmittance. A better stability of the medium and high concentrated dispersions (c ≥0.5%) comparing to most diluted dispersions even for long period (2h…24 h for Degussa based dispersions) is observed, while high concentrations (c>30%) of IPA (lower autoprotolysis tendency comparing to water), are not suitable for rendering stability of the system.

According to the double layer and DLVO theories, stabilization mechanisms are proposed: - cationic surfactants: steric hindrance and repulsions between the positively heads of DTAB molecules,

physically adsorbed onto TiO2; HTAB (C16) with a longer hydrophobic tail is less efficient; - non-ionic surfactants, polymers: steric stabilization via molecules adsorption through hydrogen bonding

with the surface hydroxyl groups of TiO2 particles, acting as efficient barriers against aggregation. Lower stability is attained when the more voluminous Triton X/ PAA/PVP molecules are adsorbed;

- anionic surfactant: SDS is favouring the particle agglomeration and rapid dispersion sedimentation, probably due to a strong decrease of the CCM in the investigated system below 100 ppm;

- capping agent: anchoring mechanism via coordination of TODA molecules onto TiO2 particle, through carboxyl/carbonyl groups interactions and surface hydroxyl groups, leads to the most efficient stabilization.

(a)

(b)

Fig 1. Stability of TiO2Degussa based dispersions, c = 0.5 %, (a) after preparation; (b) after 1h from preparation

Fig. 2 Transmittance spectra of TiO2_US based dispersions

Acknowledgements This work was performed using financial support provided by the Project CB-PhotoDeg, PN-II-PT-PCCA-2013-4-0747, contract no. 282/2014.

400 500 600 700 800

0.02

0.03

0.04

0.05

0.06

0.07

T[%

]

[nm]

after 30 min

TODA 100ppm

PEG 100ppmPAA100ppm

DTAB 100ppm

PVP 25ppm



P 6. POLYIMIDE MICRO- AND NANOPARTICLES VIA THE REPRECIPITATION METHOD

Camelia Hulubei*, Cristina-Doina Vlad, Dumitru Popovici, Irina Andreea Barzic, Daniela Rusu

“Petru Poni” Institute of Macromolecular Chemistry, 700487-Iasi, Romania *E-mail: hulubei @icmpp.ro


Polymeric micro- and nanoparticles (NP) are of strategic importance in applications such as low-k materials, medical imaging, drug delivery, as well as in fundamental studies concerning microfluidics and nanotechnology. Functional behavior of polymeric particles in these fields is strongly influenced by shape, which has a major impact in understanding and valorizing the particle function. The control of particle properties such as size and shape is essential in the development of polymeric particles as tools and products for a variety of fields. [1]

A partial-alicyclic polyimide (PI) based on bicyclo [2.2.2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (BOCA) by a two-step polycondensation reaction was synthesized. Both structural forms, the precursor of PI, poly (amic acid) (PAA), and PI, were used to prepare polymer particles (Ps) by reprecipitation, from their solutions. PAA N Ps were firstly prepared by reprecipitation, after that were converted to PI NPs through the chemical imidization of PAA NPs in the dispersion medium, with cyclodehydration reagents. PI Ps were obtained by the dropwise addition of a precipitant containing a polymer stabilizer into the polymer solution containing the same stabilizer.

Optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to evaluate the morphology of the obtained particles. Physical and chemical factors such as the polymer and stabilizer concentrations, the stirring speed, the precipitation temperature, etc., affect the size and size uniformity of the resulting particles. TEM images showed a spherical shape for the PI NPs, with a diameter in the range of 10÷700 nm. OM, SEM and TEM analyses demonstrated that the shape of PI Ps was like a sphere, ellipse or formless. Spherical particle sizes range from 30 nm to 5 μm.

Figure 1. Microscopic analysis

PI N Ps from PAA solution precipitation

PI P s from PI solution precipitation

Acknowledgements This work is financially supported from PN-II-IDPCE-2011-3-0937 Project No. 302/5.10.2011, Stage 2016. References [1] Z. Chai, X. Zheng, X. Sun, J. Polym. Sci.: Part B: Polym. Phys. 2003, 41, 159–165


P 7. POLYIMIDE SURFACES TREATMENT BY NITROGEN PLASMA FOR IMPROVEMENT OF GOLD ADHESION

Simona-Luminita Nica1*, Camelia Hulubei1, Emil Ghiocel Ioanid1, Marius Dobromir2, Silvia Ioan1

1“Petru Poni” Institute of Macromolecular Chemistry, 700487-Iasi, Romania 2“Al. I. Cuza” University, Faculty of Physics, 700506-Iasi, Romania

*E-mail: nica.simona @icmpp.ro


The study of thin metal films on flexible substrates is of great interest in fabrication of biomedical devices, such as implantable electrode arrays which consists of gold film on polymer substrates [1]. From these, polyimides are recognized as high performance systems [2], due to their excellent balance between the high mechanical and thermal properties and chemical and radiation resistance.

Two polyimides, derived from the same aromatic diamine 4,4'-oxydianiline (ODA) and two different dianhydrides, an alicyclic one, [5-(2,5-dioxotetrahydrofurfuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride (DOCDA) and an aromatic one, pyromellitic dianhydride (PMDA), were synthesized by a two-step polycondensation reaction.

The plasma-treated surfaces of the corresponding polyimide films were investigated in order to improve the adhesion between the polymer substrate and the thin metal layer deposited.

Surface properties of the polyimide films before and after modification by low pressure and high frequency plasma treatments in nitrogen, as well as of those containing thin gold layers were investigated by contact angle measurements (Table 1) and XPS analyses. Table 1. Surface tension parameters (mN m-1) for poly(DOCDA-ODA) and poly(PMDA-ODA) films according to the acid/base method (LW/AB).

The results were discussed in correlation with the chemical structure of polyimides and some

properties, such as flexibility, hydrophobicity and adhesion capacity. Acknowledgements This work is financially supported from PN-II-IDPCE- 2011-3-0937 Project No. 302/5.10.2011, Stage 2016. References [1] H.K. A. Tsai, K.-S. Ma, C. Wang, H. Xu, C. Wang, J. Zoval, L. Kulinsky, M. Madou, Smart Mater. Struct.

2007, 16, S295–S299. [2] C.E. Sroog, Prog. Polym. Sci. 1991, 16, 561–694.

poly(DOCDA-ODA)

Untreated 36.32

8.44

2.19 8.11

44.76

0.23

Plasma treated 44.22 13.68 1 46.80 57.9 0.31

Plasma treated/Au 43.77 6.40 0.55 18.5 50.17 0.15

poly(PMDA-ODA)

Untreated 39.06 1.60 0.07 9.14 40.66 0.04

Plasma treated 43.93 13.35 0.86 51.84 57.28 0.30

Plasma treated/Au 43.47 0.88 0.03 6.55 44.35 0.02


P 8. VERSATILE SiO2/npAu-TiO2/SiO2 STRUCTURES WITH ADVANCED OPTICAL AND SELF-CLEANING PROPERTIES

Ciprian MIHOREANU1*, Alexandru ENESCA2, Anca DUŢĂ3

1Renewable Energy Systems and Recycling Center, Romania 2,3Transilvania University of Brasov, Eroilor 29, 500036 Brasov, Romania,


Multilayered thin films have been extensively used for reflectivity modulation in various optical and optoelectronic devices. The performances of these devices are based on interference phenomena of alternative layers with different refractive indices.

This work presents a different approach for multifunctional glazings, that simultaneously satisfy pre-requisites of high-transmittance and self-cleaning in order to improve their effectiveness in solar-thermal collector or buildings fenestration. According to these applications, the target properties were: high transmittance and low reflectance in the UV-Vis domain, correlated with self – cleaning properties.

The SiO2 powder was synthesized by sol-gel technique, while TiO2 Degussa P25 was used for the TiO2 layers. The powders were dispersed and thin films of SiO2 and TiO2 were successively deposited by cold spraying (a cost effective, up-scalable and low energy consumption technique). The results show significant improvement in the optical properties of the solar glass used as substrate when gold nano-particles have been inserted in the SiO2/TiO2/SiO2 wafer structure. By morphology control it was possible to obtain structures with roughness values of ~20 nm; as these values are much lower than the UV-Vis wavelength (250-800 nm), multiple reflexions are promoted in the layer while the actual reflectance decreases. Additionally, the distance between neighboring grains is around 10 nm with enhance the multiple reflections. Consequently, the transmittance values have increase above 90% and the reflectance reduces below 10%. Self-cleaning based on photocatalysis activated by simulated solar radiation proved efficiencies above 60% in standard tests using methylene blue.

Figure 1. 2D AFM image, transmittance and reflectance spectra of SiO2/TiO2 multilayered thin films

Acknowledgements This work was performed using financial support provided by the Project PNII – PCCA, EST IN URBA, contract no. 28/2012.



P 9. VANCOMYCIN-PECTIN/CHITOSAN MICROPARTICLES. PREPARATION AND IN VITRO RELEASE MECHANISM STUDY

Cristian Dima1*, Popescu Maria2, Stefan Dima1

1 Dunărea de Jos” University of Galati, Faculty of Food Science and Engineering, Domnească Street, 111, RO-800201, Galati, Romania

2CHU-Guadeloupe, Pointe á Pitre /Abymes, Route de Chauvel, 97159, France *E-mail: [email protected]

Vancomycin (VM) is a glycopeptidic antibiotic used in infections due to methicillin-resistant

Staphylococcus aureus (MRSA). Because it is poorly absorbed in gastrointestinal tract, vancomycin is given intravenously for therapy of systemic infections. For Clostridium difficile infection terapy, vancomicyn is administered per os [1].

In the last years, the natural polysaccharides, such us pectin, chitosan, cyclodextrin, dextran, galactomanans, are extensively used for obtained the delivery systems of drug to the colon.

In this study, pectin/chitosan (Pc/Ch) microparticles (MP) were prepared by emulsification-internal

ionotropic gelation method and VM was entrapped as model drug [2]. Emulsification–internal gelation is a

versatile method for encapsulation of hydrophilic bioactive components [3]. To the preparation of VM-MP,

the pectin/chitosan mixtures with different mass ratio (5:1; 3:1; 1:1) were used. The VM-MP were produced

by dispersing the pectin/chitosan solution (2% w/w) containing VM (10, 15, 20 mg/L) and insoluble calcium

salt (CaCO3), into oil phase with a lipophilic surfactant (Span 80). Gelation was achieved by gentle

acidification with an oil-soluble acid that causes calcium ion release. The separation of VM-MP from the oil

phase of W/O emulsion was achieved by phase inversion using a CaCl2 solution (0.05 M). In vitro release

studies of VM-MP were performed by introducing of MP in simulated TGI fluids: simulated gastric fluid

(SGF-pH 1.5), simulated intestinal fluid (SIF-pH 6.8) and simulated colon fluid (SCF-pH 7.4). The size and

morphology of the VM-MP, the efficiency of the encapsulation, the swelling degree and release rate in

simulated fluids were studied. The results obtained are presented in Figure 1 and Table 1, and

demonstrated that the VM-pectin/chitosan MP can be used for colon drug delivery.

(a)

(b)

(c)

(d)

Figure 1. Morphology of VM-MP: a) fresh MP; b) MP in SGF; c) MP in SIF; d) MP in SCF Table 1. Characteristics of VM-MP

Polymer micro

particles Pc/Ch

(mass ratio)

Size of micro

particles (μm)

Encapsulation Efficiency

(%)

Swelling degree (Sw%) of microparticles and rate of vancomycin release (R%) after 6 hours immersion in

simulated TGI fluids (37oC)

SGF SIF SCF

Sw R Sw R Sw R

5:1 36.12±0.08 81.84±1.79 92.7 5.7±0.2 88.4 23.7±0.6 83.7 68.3±0.2

3:1 32.43±0.14 84.23±2.56 98.5 17.3±0.1 87.6 20.9±0.4 76.8 60.8±0.1

1:1 31.31±0.25 86.79±3.62 116.7 21.0±0.3 88.2 20.2±0.5 70.6 42.5±0.1

References [1] M. Popescu, Vialet R, Loundou A., Peyron F., Bues-Charbit, M., Annales Francaises d’Anesthesie et de Reanimation, 2011, 30, 726-729. [2] M. Cotarlet, S. Dima, G. Bahrim, J Microencapsul, 2013, DOI: 10.3109/02652048.2013.808279.

[3] D. J. McClements, Adv. Colloid. Interface Sci. 2015, 219, 27–53.



P 10. NEW APPROACH CONCERNING THE STUDY OF CELLULOSE ALLOMORPHS CONVERSION PROCESSES

Denisa G. Paraschiv1,2, Florin Ciolacu2*, Daniel Tampu1, Diana Ciolacu1*

1“Petru Poni” Institute of Macromolecular Chemistry, Department of Physical Chemistry of Polymers, 11 41A Grigore Ghica Voda Alley, 700487, Iasi, Romania

2“Gheorghe Asachi” Technical University of Iasi, Department of Natural and Synthetic Polymers, 71 D. Mangeron

Blvd., 700050, Iasi, Romania *E-mail: [email protected]; [email protected]


The physical properties of cellulose fibers, as well as their reactivity, are strongly influenced by the

arrangement of the cellulose molecules with the respect to each other. The association of cellulose chains creates the crystallinity of the fiber, which produce a characteristic X-ray diffraction pattern.

This study is focused on the changes in the fine structure of cellulose samples of different origins, during allomorphic conversions. X-ray diffraction method (XRD) was used to reveal the modifications in the supramolecular structure of celluloses, that occurring during each individual process of allomorphs synthesis. Cellulose I (CI) with various supramolecular arrangements (microcrystalline cellulose, cotton cellulose and dissolving pulp) was studied. Cellulose I was converted into the second crystalline form, cellulose II (CII), by mercerization processes. The crystalline form known as cellulose III (CIII) was prepared from cellulose I by the action of organic amine, followed by special treatment for removal of the reagent. Amorphous cellulose (Cam) was obtained by a method consisting in a dissolution/regeneration of cellulose in a new tri-component organic solvent system.

A particular attention was given to the influence of the allomorphic transformation towards the crystallinity and the orientations of cellulose chains in the celluloses samples. It was established that the transformation of cellulose I into other cellulose allomorphs (cellulose II, III and amorphous cellulose) is accompanied by very complex changes of the molecular and supramolecular structure. The conversion degree of cellulose allomorphs was investigated sequential during allomorphs preparation. The structural modifications were confirmed by identification of different geometries of the elementary unit of cellulose allomorph structure, reflected by XRD patterns. Acknowledgements This work was supported by a grant of the Romanian National Authority for Scientific Research and Innovation, CNCS - UEFISCDI, project number PN-II-RU-TE-2014-4-0558.




P 11. PENTACYANOFERRATE(II) COMPLEXES WITH CHITOSAN AND ITS DERIVATIVES:

SYNTHESIS, CHARACTERIZATION, AND APPLICATION

Alexander Pestov1, Dmitry Marinin2*, Veniamin Zheleznov2, Alexander Mekhaev1, Svetlana Bratskaya2

1I. Ya. Postovsky Institute of Organic Synthesis, Ural Branch of RAS, 20, S. Kovalevskoy str., Yekaterinburg 620990, Russia

2Institute of Chemistry, Far East Branch of RAS, 159, prosp.100-letiya Vladivostoka, Vladivostok 690022, Russia


Application of polymers as ligands is a powerful tool in fabrication of new functional materials,

including organic-inorganic hybrids [1]. The polymer in this process can play a role of stabilizer and dispersant due to the weak dispersion forces or non-selective ion-exchange. Formation of coordination bonds between polymer and metal ion, as an addition or substitution to the above mentioned types of interactions, significantly affects the stability of metal-polymer bonds and, therefore, properties of the resulting organic-inorganic hybrid material. Here we report on synthesis of new organic-inorganic materials based on products of interaction between sodium aminoprusside and polymer ligands (chitosan (CS), N-2-(2-pyridyl)ethylchitosan (2-PC), N-2-(4-pyridyl)ethylchitosan (4-PC), N-(4-methyl-5-imidazolyl)methylchitosan (IC), N-(2-cyanoethyl)chitosan (CC),. N-Carboxymethylchitosan (CMC), N-2-carboxyethylchitosan (CEC). The interest to fabrication of polymer-pentacyaniferrate hybrid materials is determined by their selective sorption properties toward Cs+ ions.

The composition of the obtained materials was characterized using the element analysis and X-ray diffraction; the Fourier transform infrared (FT-IR) spectroscopy, UV-visible spectroscopy, and thermogravimetric analysis. It was established that ion and ligand exchange were the main reactions at interaction of sodium aminoprusside with polymers. . It was shown that interaction between sodium aminoprusside and derivatives with strong electrondonor properties (CS, 2-PC) resulted in partial destruction of inner sphere of aminoprusside and formation of insoluble complex salts of Fe(II)/Fe(III). Analysis of the composition and structure of the obtained complexes has demonstrated that they combine in their composition pentacyanoferrate(II) in the form of Na, Fe(II/III) and chitosan salts containing water molecule or polymer amino group in the sixth coordination position. The most stable complexes with highest cation exchange capacities were obtained with CMC and CEC.

To apply these organic-inorganic composites for cesium sorption, they have been converted into the Co(II) form and characterized in terms of sorption capacities and distribution coefficients (Kd) for cesium ions. All composites have Kd values higher than that of Co(II) aminoprusside, and the highest values of distribution coefficients were obtained for polyampholyte chitosan derivatives - CMC and CEC with DS 1.0. Acknowledgements Financial support from Russian Science Foundation (project № 14-13-00136) is gratefully acknowledged.

References [1] T. Kaliyappan, P. Kannan, Prog. Polym. Sci. 2000, 25(3), 343-370. [2] P.A. Haas, Sep. Sci. Technol. 1993, 28, 2479-2506.



P 12. STRUCTURAL, MAGNETIC AND MAGNETO-OPTICAL PROPERTIES OF LEAD AND IRON -DOPED SILICO-PHOSPHATE SOL-GEL FILMS

Mihail Elisa1*, Ileana Cristina Vasiliu2, Raluca Iordanescu1, Bogdan Alexandru Sava2, Lucica

Boroica2, Mihaela Valeanu3, Victor Kuncser3

1National Institute of R & D for Optoelectronics INOE 2000, 409 Atomistilor Str., 077125, Magurele, Jud. Ilfov, Romania

2National Institute for Laser, Plasma and Radiation Physics, 409 Atomistilor Str., 077125, Magurele, Jud. Ilfov, Romania

3National Institute of Materials Physics, 105 bis, Atomistilor Str., 077125, Magurele, Jud. Ilfov, Romania *E-mail: [email protected]; [email protected]

Thin films from the system SiO2-P2O5 doped with Pb2+ and Fe2+, respectively, were obtained by sol-

gel method using pure analytical reagents. The multilayer films were deposited on silicon substrate by spin-coating technique at different rotation rates and 300oC thermal treatment after each layer deposition. As precursors, in the case of lead-doped films, tetraethoxysilane (TEOS), phosphoric acid (H3PO4) and lead nitrate, Pb(NO3)2 dissolved in CH3COOH were used and in the case of iron-doped films, TEOS, H3PO4/TEP (triethylphosphate) and ferrous chloride, FeCl2 dissolved in EtOH (ethilic alcohol) were used as starting reagents.

Magnetic and magneto-optical characterization was done by means of SQUID (Superconducting Quantum Interference Device) and MOKE (Magneto-Optical Kerr) equipment, respectively. The magnetization curves were measured at different magnetic fields (up to 6 T). As it was to be expected, the Pb2+-doped film exhibits a diamagnetic behavior. The measurements made at low magnetic field where the diamagnetic character is reduced, does not indicate the presence of some magnetic impurities. The magneto-optical measurements indicate also a diamagnetic behavior with a positive rotation for the magnetic field antiparallel to the propagation direction. A non-linear dependence of the Kerr rotation on the applied magnetic field is observed. It is seen that in the case of Pb2+-doped film, the silicon substrate has a negligible influence, maybe due to the thickness and the homogeneity of the film (Figure 1).

In the case of Fe2+-doped film, although the signal provided by the thin film is low, after subtracting the signal from the silicon substrate, the magneto-optical effect seems to be neither diamagnetic nor paramagnetitc, rather ferromagnetic taking into account that the rotation of the polarization plan does not depend linearly on the applied magnetic field (Figure 2).

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Figure 2. The dependency of the Kerr rotation angle on the magnetic induction for the Fe2+-doped film

Acknowledgements The authors are grateful to the UEFISCDI (Executive Unity for Financing of Higher Education, Research and Innovation), Romania, for the financial support in the frame of 186/2012 and 17/2012 projects-Partnership Program, 7-081/2013 M-ERA.NET project and Core Program, under the support of ANCS, project OPTRONICA IV no. PN 16.40. References [1]. M. Valeanu, M. Sofronie, A. C. Galca, F. Tolea, M. Elisa, B. Sava, L. Boroica and V. Kuncser, J. Phys. D: Appl. Phys., 2016, 49, 075001 (10pp). [2]. M. Sofronie, M. Elisa, B. A. Sava, L. Boroica, M. Valeanu, and V. Kuncser, Rev. Sci. Instrum., 2015, 86, 053905-1, 053095-7.

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P 13. FUEL CHARACTERISTICS OF WATER-IN-OIL MICROEMULSIONS BASED ON

DIESEL AND DIESEL-RAPESEED OIL. RHEOLOGICAL, STRUCTURAL AND

COMBUSTION STUDIES

Florentina-Cristina Mihăilescu1, Marieta Balcan1, Dan-Florin Anghel1*, Ludmila Aricov1, Elena-Livia

Simion1, Iulia Contineanu2, Daniela Gheorghe2, Speranța Tănăsescu2

1Colloid Chemistry Laboratory, Ilie Murgulescu” Institute of Physical Chemistry, Romanian Academy, Spl. Independentei, No. 202, 060021, Bucharest, Romania,

2Chemical Thermodynamic Laboratory, Ilie Murgulescu” Institute of Physical Chemistry, Romanian Academy, Spl.

Independentei, No. 202, 060021, Bucharest, Romania E-mail: [email protected]; [email protected]


In this study, the fuel properties of water-in-oil (w/o) microemulsions containing diesel and diesel-

rapeseed oil (RSO) mixtures are investigated. These systems containing up to 10% wt. water were prepared without electrolyte, by using environmentally friendly surfactants. They were mixtures of different nonionic surfactants Brij 30 (B30), Igepal CO-520 (NPEO5) and Tween 65 (T65), the anionic surfactant Synperonic A9C (Na) (SA9C), and the cosurfactant i-butanol (B).

The rheological behavior of these systems were investigated in the 10 - 60ºC temperature range. The dynamic viscosity values of fuel microemulsions (FME) decrease with the temperature and they are slightly higher than those of diesel and vegetable oil. The values increase with the water content, the molecular weight of nonionic surfactant and in the presence of the RSO. These FME have a good temperature stability and Newtonian behavior. The DLS data reveal that the water particles of FME are in the nanometric domain. A decrease in time of the nanometric particles amount and the appearance of micrometric particles accompanied by a lowering of dynamic viscosity was observed. The flow properties at low temperature and calorific values are comparable to those of diesel oil. The results obtained provide valuable information on formulation and preservation of microemulsions as alternative fuels for diesel engine. Acknowledgements The research for this paper has been carried out within the Functional Complex Colloids Program of the ‘Ilie Murgulescu’ Institute of Physical Chemistry, financed by the Romanian Academy. The authors gratefully acknowledge the support of the EU (ERDF) and Romanian Government allowing for acquisition of research infrastructure under POS-CCE O 2.2.1 project INFRANANOCHEM, No. 19/01.03.2009. This work is also supported by the PN-II-ID-PCE-2011-3-0916 Exploratory Research Project.




P 14. HETEROGENEOUS DISTRIBUTION OF CARBON NANOTUBES (CNTs) AS DECISIVE FACTOR OF PROPERTIES OF CONDUCTIVE THERMOPLASTIC COMPOSITES

Fulga Tanasă1*, Mădălina Zănoagă1, Yevgen Mamunya2

1 “Petru Poni” Institute of Macromolecular Chemistry, 41A Grigore Ghica Vodă Alley,700487, Iasi, România 2 Institute of Macromolecular Chemistry, National Academy of Sciences of Ukraine, 48 Kharkivske chaussee,

02160, Kyiv, Ukraine * E-mail: [email protected]


The heterogeneous distribution of conductive phase in conductive thermoplastic composites - used

as antistatic materials, low temperature heaters, materials for electromagnetic irradiation (EMI) shielding, and for various sensors - is known to grant low and ultralow percolation treshold values to the corresponding materials [1]. Such distribution of the filler particles may be successfully reached when dual polymer matrices, such as blends of two thermoplastic polymers with different viscoelastic properties, are employed [2]. By this approach, the conductive phase is partitioned between the two consisting polymers and a specific co-continuos morphology is created. This striking feature is responsible for the so called “double percolation phenomenon” [3] when the conductive filler is localized either in one polymer phase or at their interface.

Considering carbon nanotubes (CNTs) as an excellent choice of conductive filler, given their unparalleled characteristics, the selection of polymers for novel thermoplastic composites was made aiming not only low percolation threshold values [4], but low melting intervals as well, without sacrificing electrical and mechanical properties [5,6]. It was proven that the incorporation of CNTs into a polymer blend is affecting the morphology of the composite and parameters of specific interactions between constituents [1].

This paper presents the results obtained for novel thermoplastic composites made of two different polymers (high density polypropylene PP and low viscosity copolyamide coPA with a low melting temperature) and using multi-walled carbon nanotubes (MWCNTs) as conductive filler. The experimental conditions granting the heterogeneous distribution of the filler particles were also evaluated. Thus, the data obtained indicated that the percolation threshold is strongly related to the spatial distribution of MWCNTs inside the matrix and the value depends on the method of preparation of composites. Overall, the behavior of these composites complied with the concept of the double percolation. References

[1]. Y. Li, H. Shimizu, Macromolecules 2008, 41, 5339-5344. [2]. G. Boiteux, Y. Mamunya, E. Lebedev, A. Adamczewski, C. Boullanger, P. Cassagnau, G. Seytre,

Synth. Met. 2007, 157, 1071-1073. [3]. M. Sumita, K. Sakata, S. Asai, K. Miyasaka, H. Nakagawa, Polym. Bull. 1991, 25, 265-271. [4]. L. Zhang, C. Wan, Y. Zhang, Compos. Sci. Technol. 2009, 69, 2212-2217. [5]. R. Cardinaud, T. McNally, Eur. Polym. J. 2013, 49, 1287-1297. [6]. E. Cohen, L. Zonder, A. Ophir, S. Kenig, S. McCarthy, C. Barry, J. Mead, Macromolecules 2013,

46, 1851-1859.



P 15. FeNPs/ ZnMe(Me=Al3+, Cr3+, Fe3+) SELF-ASSEMBLED NANOARCHITECTURES FOR APPLICATIONS IN PHOTO-FENTON CATALYSIS

Marius Sebastian Secula, Mihaela Darie, Gabriela Carja*

Chemical Engineering Department, Faculty of Chemical Engineering and Environmental Protection, Gheorghe Asachi Technical University, Prof. Dr. docent Dimitrie Mangeron 73, 700050, Iasi, Romania


Persistent organic pollutant discharged by urban regions or industry into the aquatic ecosystems

represents a serious threat to fauna and human health. In this context recent studies conducted by WHO (World Health Organization) revealed that endocrine disrupting compounds present toxic effects even at low concentration. One such potential endocrine disrupting compound is Ibuprofen. The use of light energy to accomplish the latest requirements concerning wastewater discharge demands highly-performant and robust photocatalysts. Among the promising photocatalysts, layered double hydroxides (LDHs) attracted significant consideration mainly due to their composition flexibility, high surface area and tailored redox features [1].

This work presents the self-supported Fe(II) on ZnMeLDHs (Me =Al3+, Cr3+, Fe3+) as novel efficient photocatalysts for Fenton-like catalysis. The coprecipitation method was used to prepare ZnAlLDH, ZnFeAlLDH and ZnCrLDH (Zn2+/Me3+ = 2 molar ratio). Nanoparticles of iron oxides were self-supported on the LDHs matrices by using the reconstruction method, at two different values of weight concentration. X-ray diffraction (XRD), thermogravimetric analysis (TG/DTG), Fourier transform infrared (FTIR) and transmission electron microscopy (TEM) were used to investigate the structural, textural, and micromorphology of the catalysts. The Fe(II)/ZnMeLDHs nano-hybrids were tested for the degradation of a model pharmaceutical agent, the anti-inflammatory agent ibuprofen, by photocatalysis and photo-Fenton catalysis, respectively. Results point out that the embedment Fe(III)/Fe(II) into ZnFeAlLDH and ZnCrLDH results in a slight enhancement of ibuprofen degradation by light irradiation, whereas in case of ZnAlLDH, the degradation process is relatively low. A remarkable enhancement of ibuprofen degradation was found in the case of Fe(II)/ZnMeLDHs by photo-Fenton process (Figure 1).

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Acknowledgements This work was supported by Romanian National Authority for Scientific Research and Innovation, CNCS – UEFISCDI under the projects PN-II-RU-TE-2014-4-0405 and PNII-IDEI 75/2013. References [1] R. Smith, B. Brown, K. Young, J.Appl.Polym.Sci. 2009, 42, 2113-2117. E.M. Seftel, M.C. Puscasu, M.

Mertens, P. Cool, G. Carja, Applied Catalysis B: Environmental, 2015,164, 251-260.



P 16. FLEXIBLE GUANOSINE-BASED HYDROGELS FOR BIOMEDICAL APPLICATIONS

Gabriela Pricope*, Dragos Peptanariu, Alexandru Rotaru, Mariana Pinteala, Mihail Barboiu Centre of Advanced Research in Bionanoconjugates and Biopolymers, ‘‘Petru Poni’’ Institute of Macromolecular

Chemistry, Aleea Grigore Ghica Voda 41A, 700487 Iasi, Romania *E-mail: [email protected]


A new supramolecular hydrogel system based on guanosine quartet (G-quartet) assembly was prepared by reacting guanosine with corresponding equivalent of 1,4-phenyl diboronic acid in KOH. The resulting guanosine-boronic esters self-assemble in the presence of K+ ions, forming a stable hydrogel with middle to high water content. The G-quartet formation inside the hydrogel structure was confirmed by following the characteristic signals in circular dichroism. The tissue engineering performance of obtained hydrogel was confirmed by preliminary cell viability test on NHDF (Normal Human Dermal Fibroblasts) cell line, showing a good viability of NHDF cells at the hydrogel surface. These tests involved the use of top-cut syringe to mould the hydrogel in a cylindrical shape and after that the obtained sample was immersed for 24 hours into TAE buffer solution (pH=7.00) enriched with magnesium to prevent gel swelling. Water rinsed thin lens-like section of the gel was placed into a cell-culture plate with alpha-MEM cell culture medium supplemented with 10% fetal bovine serum, 1% Penicillin-Streptomycin-Amphotericin B mixture, 10K/10K/25 μg and left in the humidified incubator at 37ºC and 5% CO2. After 24 hours the culture medium was replaced with a new one and the NHDF cell suspension was added. After 72 hours of cultivation, the optical microscope investigation revealed the successful cells adhesion to the gel’s surface.

Additionally, preliminary results have shown that the prepared hydrogels could also be stabilized by using Ba2+ and Mg2+ ions, yielding in an ultra-high water content hydrogels, suitable for other biomedical applications, including dynamic drug delivery systems. Studies on the structure and properties of the guanosine-based hydrogels stabilized with Ba2+ and Mg2+ ions will be reported in due course. Acknowledgement

The authors are grateful to “Petru Poni” Institute of Macromolecular Chemistry for the financial support of

this work via ERA Chairs Project (Grant Agreement No. 667387, Call Horizon 2020 WIDESPREAD 2-2014)

and the Romanian National Authority for Scientific Research and Innovation, CNCS – UEFISCDI (project

number PN-II-RU-TE-2014-4-1444).



P 17. STEROLS IN DATURA INOXIA AS POTENTIAL KEY SOURCE SPECIFIC TRACERS FOR ORGANIC COMPONENTS IN AMBIENT ATMOSPHERIC AEROSOL PARTICLES

Georgiana Mardare (Balusescu)1*, Romeo Iulian Olariu1,2, Cecilia Arsene1,2*

1”Alexandru Ioan Cuza” University of Iasi, Faculty of Chemistry, Department of Chemistry, 11 Carol I, 700506 Iasi, Romania

2”Alexandru Ioan Cuza” University of Iasi, Integrated Center of Environmental Science Studies in the North Eastern Region – CERNESIM, 11 Carol I, 700506, Iasi, Romania


Biomass burning releases into the atmosphere large amounts of particulates and gases, highly

impacting air quality and climate. It is assigned as the second largest source of trace gases and the largest source of primary fine carbonaceous particles in the global troposphere [1]. Natural molecular biomarkers (organic compounds of a biological origin) include sterols, triterpenols, triterpenones and diterpenoid acids. Restricted occurrence, source specificity, molecular stability and suitable concentration for analytical detection are major characteristics of such natural biomarkers [2]. Since sterols are ubiquitous constituents of all biota (except bacteria), characterized by relatively high stability and specific distribution in different environments, their analyses can provide a means of determining the origins of organic materials in the environment [3]. Sitosterol, stigmasterol and campesterol are major sterols synthesized by higher plants while lower plants contain a different sterol unit’s distribution. Direct burning of higher plants is already assigned as a source of phytosterols in ambient aerosol particles.

In Romania, Datura inoxia, a higher dicotyledons plant [4], is usually used for decorative purposes. Taking into account its potential to trace specific organic components this plant has been investigated in the present work for a complete characterization of its specific “chromatographic fingerprint”. Compounds such as squalene, campesterol, γ-sitosterol, stigmasterol and fucosterol have been identified beside other components by gas-chromatography-mass spectrometry (GC-MS) technique. Ultrasonic extraction efficiencies in various organic solvents (methanol, MeOH, ethanol, EtOH, butanol, BuOH) has been investigated for the previously mentioned compounds identified in different Datura inoxia structural units (flowers, seeds, leaves). An interesting behavior has been observed for squalene, the precursor in sterols biosynthesis process. It has been observed that this compound is mainly distributed within seeds structural units with abundances of ~23% in both EtOH and BuOH organic solvents. Campesterol, stigmasterol, γ-sitosterol and fucosterol have been extracted by most of the investigated solvents. However, these compounds have been observed to prevail mainly in flowers (abundances between 4.9-9.9%) when compared to their abundances in leaves (abundances in the 1.4 and 6.0% range) or seeds (abundances in the 1.6 and 3.1% range). Another extraction technique, i.e. Quick Easy Cheap Effective Rugged and Safe (QuEChERS), applied on Datura seeds structural units in methanol, lead us to similar information revealing prevalence of squalene over sterol abundances. However, work on QuEChERS extraction method is still ongoing since its efficiency is much smaller when compared to that specific for ultrasonification (e.g., squalene with ~4.8% contribution by QuEChERS when compared to ~13% contribution from ultrasound assisted extraction). Quantitative aspects for the identified sterols are also among our further concerns since this will help us to make a clear estimation of their potential contribution to the ambient aerosol particles. Moreover, we think that these biomarker tracers will be suitable to investigate the transport and fate processes of biomass burning smoke emissions in the area of interest environment. Acknowledgements The authors acknowledge the financial support provided by UEFISCDI within the PN-II-PCE-2011-3-0471 Project. CERNESIM Center is gratefully acknowledged for the infrastructure used in this work. References [1] S.K. Akagi, R.J. Yokelson, C. Wiedinmyer, M.J. Alvarado, J.S. Reid, T. Karl, J.D. Crounse, P.O.

Wennberg, Atmos. Chem. Phys. 2011, 11, 4039-4072. [2] B.R.T. Simoneit, J.Appl.Geochem. 2002, 17, 129-162. [3] D.R. Oros, M. Radzi bin Abas, N.Y.M.J. Omar, N.A. Rahman, B.R.T. Simoneit, J.Appl.Geochem.

2006, 21, 919-940. [3] R.C. Urban, C.A. Alves, A.G. Allen, A.A. Cardoso, M.L.A.M. Campos, J.Atmos.Res. 2016, 169-271. [4] S.D., Purohit, Introduction to plant cell tissue and organ culture, Ed. PHI Learning, Delhi, 2013, p. 178.



P 18. CELLULOSE PHOSPHATE MICROPARTICLES FOR DYES ADSORPTION

Dana M. Suflet, Irina Popescu*, Irina M. Pelin Petru Poni Institute of Macromolecular Chemistry, Aleea Grigore Ghica Voda, 700487 Iasi, Romania



Dyes are widely used in pharmaceutical, cosmetic, textiles, or food industries. Some dyes and their degradation products may be mutagenic, allergenic, or carcinogenic. Consequently, they are important sources of water pollution and their treatment becomes a major problem [1]. In recent decades, several physical, chemical and biological techniques have been reported to remove dyes from wastewater including adsorption, coagulation, membrane separation, chemical oxidation, photocatalytic degradation, electrochemical and aerobic and anaerobic microbial degradation, etc. From all of these, adsorption is one of the most effective and feasible method for the wastewater treatment owing to high efficiency, ease of operation and insensitivity to toxic pollutants. In recent years, many efforts have been spent in developing the low-cost and high effective adsorbents, such as natural materials, biosorbents, and solid wastes from agriculture and industry.

Cellulose is the most abundant natural polymer and thus one of the most potential resources able to replace oil based synthetic polymers. Moreover, the properties of this natural polymer, including renewability, biodegradability, wide availability, and non-toxicity results in the development of a new class of adsorbents based on cellulose and its derivative [2, 3].

In the present work, we focused our attention on the synthesis of new anionic microparticles based on monobasic cellulose phosphate [4], and on the study of their adsorption capacity for different cationic dyes. The 20-40 μm microparticles were prepared by chemical cross-linking using the water-in-oil inverse emulsion technique. The effect of different parameters such as adsorbent dose, initial dye concentration, initial pH, and contact time on their dye adsorption capacity was studied using the batch-adsorption technique. The equilibrium adsorption data were analyzed by Langmuir and Freundlich isotherms, whereas kinetic data were analyzed using pseudo first order, pseudo second order, intra-particle diffusion, and Boyd’s models [5]. Linear fitting of the adsorption data suggested that the equilibrium adsorption process followed the Langmuir adsorption isotherm model, whereas, the kinetic adsorption process followed pseudo-second order model. The multi-linearity observed in the intra-particle kinetic plots suggested that the adsorption is not controlled by diffusion. These results were also confirmed by Boyd’s model. Acknowledgements This work was supported by a grant of the Romanian Ministry of Education, CNCS – UEFISCDI, project PN-RU-TE-2014-4-0437. References [1] K.B. Tan, M. Vakili, B.A. Horri, P.E. Poh, A.Z. Abdullah, B. Salamatinia, Sep. Purif. Technol. 2015,

150, 229–242. [2] I.A. Udoetoka, R.M. Dimmicka, L.D. Wilsona, J.V. Headley, Carbohydr. Polym. 2016, 136, 329-340. [3] H. Kono, R. Kusumoto, J Water Process Eng. 2015, 7, 83-93 [4] D.M. Suflet, G.C. Chitanu, V.I.Popa, React. Funct. Polym. 2006, 66, 1240–1249. [5] N. K. Goel, V. Kumar, N. Misra, L. Varshney, Carbohydr. Polym. 2015, 132, 444–451.



P 19. CRYSTALLIZATION DYNAMICS OF SOME COPOLYAMIDE-CLAY HYBRID MATERIALS AS FUNCTION OF FILLER CHARACTERISTICS

Mădălina Zănoagă*, Cristian V. Grigoras, Fulga Tanasă

“Petru Poni” Institute of Macromolecular Chemistry, 41A Grigore Ghica Vodă Alley 700487, Iasi, România * E-mail: [email protected]


Structural changes in hybrid materials yield in modified properties. The polymer crystalline regions

behave as barriers, while the final properties are an expression of the crystallinity changes. It is known that fillers can act as nucleation centers and, subsequently, may partially hinder the matrix crystallization. This characteristic, in association with the degree of intercalation/exfoliation which enables hybrids an enhanced tortuosity, can explain their permeability as a function of both diffusivity and solubility, depending on the crystalline/amorphous ratio [1].

The aim of this paper was to study, by the means of DSC, the crystallization dynamics of some new hybrid materials containing 5% clay. A series of three copolyamide-clay hybrid nanocomposites were prepared using three different smectite clays (bentonite, montmorillonite K10 and Nanomer I.30P) by a solventless melt mixing process. The matrix was a ternary copolyamide (PPIMC patent) selected not only for its properties and applicative potential, but for theoretical reasons as well, given the scarce literature data on composites and hybrids based on aliphatic copolyamides with complex structures.The thermal gravimetric analysis concluded that all hybrids displayed enhanced thermal stability due to the interfacial interactions between clay particles and matrix. Therewith, the presence of transition metals (Fe, Mn, Ti, Cu) in clays as impurities may contribute to this increased thermal stability.

The experimental data clearly indicated that the nature of clay, the particles size and their granulometric distribution determine the crystallization dynamics, as well as the nature, shape, and stability of crystallites. The presence of distinct morphological entities that contain instable crystals (which melt arround 100oC) and of some epitaxial crystallites developed on the clay platelets, which are very stable and display highly defined shapes (that melt above 130oC), was evidenced. References

[1]. B. Alexandre, D. Langevin, P. Médéric, T. Aubry, H. Couderc, Q.T. Nguyen, A. Saiter, S. Marais, J. Membr. Sci. 2009, 328, 186–204.



P 20. NICKEL COMPLEXES OF GUANIDINE FUNCTIONALIZED SILOXANES

Lucia Pricop, Maria Emiliana Fortuna*, Daniel Ţampu, Valeria Harabagiu 1”Petru Poni” Institute of Macromolecular Chemistry, 41A, Gr. Ghica Voda Alley, 700487 Iasi, Romania,



Considerable efforts in the development of methods for the immobilization of homogeneous

transition-metal catalysts on organic polymers were performed. Homogeneous catalysts offer the advantage of high selectivity and mild reactions conditions, while heterogeneous catalysts, although generally more active and less selective, are more durable and more easily separated from the reaction products. By anchoring a homogeneous catalyst to a polymer, the advantages of both types of catalysts can be combined [1]. Supported nickel catalysts comprise one of the most important classes of heterogeneous catalysts, due to the widespread applications of these systems, like methanation, partial oxidation, and steam reforming [2].

In this direction, the present study reports on a methodology for the preparation of a new complex consisting of nickel coordinated to 1,1,3,3 – tetramethylguanidine functionalized polysiloxane. The complex have been characterized by NMR analysis, FT-IR and X-ray diffraction, as well as by differential scanning calorimetry (DSC), UV-Vis spectroscopy, scanning electron microscopy. Acknowledgements: This work was partially supported by the project STHEMOWTB, contract MENCS-UEFISCDI no. 59/2014. References [1] L.A. van de Kuil, D.M. Grove, J.W. Zwikker, L.W. Jenneskens, W. Drenth, G. van Kotent, Chem. Mater. 1994, 6, 1675-1683. [2] Juan C. De Jesusa, I. Gonz´alezb, A. Quevedob, T. Puertab, J.of Molec. Catalys., A: Chem. 2005, 228, 283–291.



P 21. ORGANIC FUNCTIONALIZED GRAPHENE OXIDE AS A COMPOSITE MATERIAL WITH MULTIPLE APPLICATIONS

Petre Ionita1,2*, Ahmed J. Shakir2, Ioana Turcu,2 Anca Coman2

1Institute of Physical Chemistry, 202 Spl. Independentei, Bucharest, Romania 2University of Bucharest, Faculty of Chemistry, 90-92 Panduri, Bucharest, Romania


TEMPO (2,2,6,6-tetramethylpiperidin-1-yl)oxyl, a stable nitroxide free radical) was covalently

grafted on graphene oxides (GO) through an amide bond and the new composite solid materials were characterized by thermal analysis, infrared, Raman and electron spin resonance spectroscopy. It was found that TEMPO functionalized GO can be successfully used as recoverable solid catalysts for selective oxidation of alcohols, using NOx as cocatalyst and air as final oxidant, under very mild conditions. Other possible applications of organic functionalized GO are underway.

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Functionalization of GO with TEMPO was performed in two steps: in the first step the activation of

COOH groups from GO was achieved by transforming them into the corresponding acid chloride COCl; the second step is represented by the reaction of COCl with 4-amino-TEMPO (Fig. 1). The materials thus obtained were used in the selective oxidation of five alcohols (benzyl alcohol, 1-phenylethanol, diphenylmethanol, furfuryl alcohol and 1-octanol) into the corresponding aldehydes and ketones. The oxidation yield depends on the reactivity of the alcohols, i.e. benzyl alcohol can be oxidized selectively to benzaldehyde in an almost quantitative yield.

Using a similar procedure, other compounds of interest can be immobilized on GO. In a separate experiment, a crown ether compound (4-aminobenzo-15-crown-5 ether, B15-C-5) was covalently linked to the GO. It is well known that GO can remove many contaminants from water, including heavy metal ions or polyaromatics, due to specific interactions. Our aim is to provide a solid material able to lower simultaneously the amount of several such contaminants. Experiments are in progress. Acknowledgements This work is dedicated to the 150th Aniversary of the Romanian Academy and was supported by a grant from the Romanian National Authority for Scientific Research, CNCS – UEFISCDI, project number PN-II-ID-PCE-2011-3-0408.



P 22. FAST REMOVAL OF AMARANTH DYE FROM WASTEWATERS USING COBALT FERRITE

Razvan Rotaru*, Petrisor Samoila, Corneliu Cojocaru, Petronela Pascariu Dorneanu, Liviu

Sacarescu, Valeria Harabagiu "Petru Poni" Institute of Macromolecular Chemistry, Grigore Ghica Voda Aley, 41A, 700487 Iasi, Romania



Industrial processes as well as the normal households generate persistent organic chemicals with

adverse impacts on water resources. Most of the pollutants are complex organic molecules which are often difficult to degrade, such as phenolic compounds, dyes and others. The conventional wastewater treatment technologies based on biological, thermal, and physicochemical processes have limitations in terms of applicability, effectiveness and costs [1]. Therefore, the development of new efficient systems for wastewater treatment represents a great challenge for the researchers.

In this respect, heterogeneous catalytic wet hydrogen peroxide oxidation (CWHPO) processes are extremely attractive enabling the complete mineralization of refractory organic pollutants into carbon dioxide, water and other innocuous inorganic compounds [1]. The objective of this work is to study the efficiency of cobalt ferrite in CWHPO of Amaranth azo dye.

Pure CoFe2O4 was prepared by the sol-gel auto-combustion method using citric acid as fuel [2]. The crystal structure and surface morphology of the catalyst were characterized by infrared spectroscopy (FT-IR), X-ray diffraction analysis (XRD) (Figure 1) and transmission electron microscopy (TEM).

20 30 40 50 60 70 80

Inte

nsity (

a.u

.)

2(degrees)

400 450 500 550 600 650

0.0

0.2

0.4

Wavelength (nm)

Ab

so

rban

ce

0 min*

5 min

15 min

30 min

60 min

120 min

*dilution factor (f=8)

Figure 1. XRD pattern for CoFe2O4 catalyst

Figure 2. Spectral response of 100mg/L Amaranth dye during the catalytic degradation (4 g/L CoFe2O4,

20 mM H2O2, pH = 1.5, T=75 ºC) The degradation by CPHWO processes of Amaranth azo dye was investigated at 75 ºC. For a typical

run, 50 ml of dye solution was taken and heated up to the required temperature. 0.2 g catalyst, 20 mM of hydrogen peroxide and a certain volume of HNO3 (20%) were consequently added. This was taken as zero time in all experiments. The concentration of amaranth dye was varied in the range of 10 to 100 mg/L. During the oxidation processes, reaction mixture withdrawn from the reaction system at selected time intervals was analyzed using UV-VIS Spectrophotometer in the range 375-650 nm. An extremely fast color removal (15 min) even at high pollutant concentration (Figure 2) was observed.

Acknowledgements This work was supported by a grant of the Romanian National Authority for Scientific Research and

Innovation, CNCS – UEFISCDI, project number PN-II-RU-TE-2014-4-1266. References [1] F. Martınez, J.A. Melero, J.A. Botas, M.I. Pariente, R. Molina, Ind. Eng. Chem. Res. 2007, 46, 4396-

4405. [2] P. Samoila, C. Cojocaru, I. Cretescu, C.D. Stan, V. Nica, L. Sacarescu, V. Harabagiu, J.Nanomater.

2015, ID 713802.



P 23. SOLVENT TUNABLE SELF-ASSEMBLY OF AN AMPHIPHILIC POLYTHIOPHENE IN “HAIRY-ROD” ARCHITECTURE: POLYMERIC NANOSTRUCTURES WITH VARIABLE

SHAPE AND SIZE

Luminita Cianga*, Anca-Dana Bendrea, Elena Gabriela Hitruc, Ioana-Andreea Turin-Moleavin, Ioan Cianga

“Petru Poni” Institute of Macromolecular Chemistry, 41A Grigore Ghica Voda Alley, 700487, Iasi, ROMANIA *E-mail: [email protected]


Polythiophenes are one of the most important classes of conjugated polymers with a wide range of

applications in almost all type of polymer electronics [1], while their applicability as fluorescent markers of cells [2] or as bioactive platform in relation with cells and proteins was established as well [3-6]. Electronic devices properties, function and performance sensitively depend on both CPs chain conformation as well as intra- and inter-polymer chain interactions. Some experimental evidences suggest that the “memory” of the solution phase is retained in thin films through solution processing and that, the devices improved performance is definitely influenced by films having ordered structures from the nano- to macroscale.

Solution phase colloidal self-assembly of amphiphilic conjugated polymers offers a way to fabricate nanoscale building blocks of conjugated polymers with well-ordered packing structures. However, despite the technological relevance and fundamental interests, colloidal self-assembly of rod−coil type amphiphilic polymers remains much less understood [7]. Conjugated rod-coil copolymers in “hairy–rod” architecture (HR-CPs), best described as "molecularly reinforced liquids"[2] become an exciting research field for the new materials having unexpected properties otherwise impossible to be obtained with the polymers with common topology. The convergence of biodegradable and biocompatible polymers with conjugated ones offers abundant opportunities to produce complex materials, appropriate for both environmentally biodegradable “green” electronics and bioresorbable temporary medical devices.

S

R1

S

R2

0.66 0.34O OCH3

O

O OH

O

R1:

R2:

44

18

Figure 1. Structural units formula of amphiphilic polythiophene copolymer PTh-Cop

Taking in account this strategy, the amphiphilic polythiophene reported in this communication

combines in its structure biocompatible and hydrophilic polyethylene glycol (PEG) side chains with

biodegradable and hydrophobic poly--caprolactone (PCL). The influence of the solvent nature as well as the solution concentration on the morphology, size and photophysical properties of PTh-Cop have been investigated in detail using AFM, DLS, UV-vis and fluorescence measurements. Four organic solvents (acetonitrile, acetone, chloroform and toluene) were deliberately chosen to change their selectivity toward the different hydrophilic/hydrophobic character of the grafted chains and PTh- conjugated backbone. The type of morphology resulted due to intramolecular phase segregation, evidenced by AFM, varied from globular Janus type nanoparticles (formed in compatible solvents for the conjugated main chain) to “core-shell” micellar short rods or vesicles in poor ones. While in chloroform and acetone the size and shape of the self-assembled entities are concentration dependent, in toluen and acetonitrile only their size were influenced by this parameter.

References [1] Handbook of Thiophene-based Materials: Applications in Organic Electronics and Photonics, I.F. Perepichka, D.F. Perepichka Eds. John Wiley and Sons, 2009. [2] L. Cianga, A.-D. Bendrea, N. Fifere, L. E. Nita, F. Doroftei, D. Ag, M. Seleci, S. Timur, I.Cianga, RSC Adv, 2014, 4, 56385–56405. [3] M.M. Perez-Madrigal, L. Cianga, L.J. del Valle, I. Cianga, C. Aleman, Polym. Chem. 2015, 6, 4319-4335. [4] S. Maione, G. Fabregat, L. J. del Valle, A.-D. Bendrea, L. Cianga, I. Cianga, F. Estrany, C. Aleman, J. Polym.Sci. Part B Polym Phys., 2015, 53, 239-252. [5] A.-D. Bendrea, G.Fabregat, L. Cianga, F. Estrany, Luis J. del Valle, I. Cianga, C. Aleman, Polym. Chem. 2013, 4, 2709-2723. [6] A.-D. Bendrea, G. Fabregat, J. Torras, S. Maione, L. Cianga, Luis J. del Valle, I. Cianga, C.Aleman; J. Mater.Chem. B. 2013, 33, 4135-4145. [7] A.C. Kamps, M.H.M. Cativo, M. Fryd, S.J. Park, Macromolecules, 2014, 47, 161-164.


12th international conference on colloid and surface chemistry

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