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  • Slide 1
  • Inorganic / Organic Nanocomposite Research Peter Kofinas Associate Professor Department of Chemical Engineering University of Maryland College Park, MD 20742-2111
  • Slide 2
  • Research Programs l Chemical Engineering o Sheryl Ehrman: Monodisperse Nanoparticle Processing o Tracey Holoman: Nanoparticle Interactions with Cells o Peter Kofinas: Block Copolymer Nanocomposites, Bioactive Hydrogels o Srinivasan Raghavan: Polyelectrolytes, Complex Fluids Rheology l Materials and Nuclear Engineering o Robert Briber: Neutron Scattering, Polymer Physics o Luz Martinez-Miranda: Liquid Crystals, Magnetic Nanoparticles o Otto Wilson: Biomimetic Materials
  • Slide 3
  • Synthesis of Monodisperse Metal Nanoparticle Standard Materials Sheryl H. Ehrman, Dept. of Chemical Engineering Funding: National Institute of Standards and Technology Objective: Synthesize size monodisperse metal nanoparticles for use as standard materials for validating light scattering models. Results are used for improving detection of contaminant particles on surfaces. Approach: Use of a novel co-solvent spray pyrolysis process to produce reduced metal nanoparticles, starting from inexpensive metal salt precursors. Size selection is accomplished via electrical mobility classification. Accomplishments: Synthesis and deposition of monodisperse (geometric standard deviation =1.03) copper particles for use in light scattering studies. Extension of this approach to other materials. Impact: Improved ability to detect surface contaminants will lead to increased yield in many manufacturing processes. h
  • Slide 4
  • Porous Materials from Nanoparticle Agglomerates Sheryl H. Ehrman and John N. Kidder Dept. of Chemical Engineering, Dept. of Materials and Nuclear Engineering Funding: University of Marylands Small Smart Systems Center Objective: Develop a particle formation-CVD process to produce porous films from nanoparticles. Approach: Use vertical furnace reactor and cold deposition stage to synthesize and deposit nanoparticles. Accomplishments: Rapid growth of porous alumina films Extension to multicomponent platinum/ alumina catalytic films Impact: Process is scalable. Substrate is kept at low temperatures enabling deposition onto polymeric membranes and other materials with low thermal stability. thermocouple three zone furnace cooling water in cooling water out sampling stage substrate to filter, cold trap, and exhaust metal organic precursors in TEM images of alumina aggregates
  • Slide 5
  • Interactions Between Nanoparticles and Microbial Cells Sheryl H. Ehrman and Tracey R. Pulliam Holoman, Dept. of Chemical Engineering Luz Martinez-Miranda, Dept of Materials and Nuclear Engineering Funding: ONR 0104127677 Objective: Study fundamental interactions between nanoparticles and cells. Approach: Culture E.coli bacteria in the presence of silica and iron oxide nanoparticles to determine effect of presence of nanoparticles on growth and cell health. Accomplishments Initial results suggest nanoparticles are not toxic to cells. Work continues towards functionalizing magnetic nanoparticles to bind to specific cell types and induce magnetoporation. Impact Knowledge of nanoparticle/cell interactions important for development of new technologies for sensing biomolecules, and for new in-vivo diagnostic and treatment capabilities. E.coli nanoparticles
  • Slide 6
  • Study of liquid crystals and related nanometer materials L. J. Martnez-Miranda, University of Maryland; NSF ECS-95-30933 l Objective: To study defect structures in the nanometer, micrometer level, by using Grazing Incidence X-ray diffraction. l Applications: A detailed study of the effect of the substrate surface in Flat Panel Display Devices l Approach: Use GIXS to study the defect structure in detail. Compare to different models. l Accomplishments: One of the first groups to study the structures as a function of thickness, depth (incidence angle) and temperature of the films.
  • Slide 7
  • Alignment of Magnetic Biomimetic NanoParticles (O. Wilson, Jr, L. J. Martnez-Miranda (U of Maryland) UMCP GRB They undergo a phase transition as illustrated to the right, similar to what liquid crystals undergo in grated surfaces. We find that in grated surfaces the particles form a striped domain Structure, as shown on top. Objective: To see how the particles align in different surfaces Applications: To look into the information they can provide on bone reconstruction 1 235 4
  • Slide 8
  • Sugar Binding Polymeric Molecular Imprints Peter Kofinas Objective: Development of novel biomaterials using aqueous synthesis techniques for molecular imprinting Ionic imprinting against glucose Ionic imprinting possibilities of other sugars Impact: Treatment and management of type II diabetes mellitus and obesity Applications: Pharmaceutical, Food Additive, Isomer Separations, Chemosensors, Catalysis Approach: Ionic imprint association during polymer crosslinking and subsequent removal Creation of sugar-specific binding sites Measurement of sugar transport and binding selectivity Accomplishments: Glucose imprinted polymers exhibit significant specificity for glucose over fructose Crosslinker and template quantity affect specificity and binding capacity Polymer Hydrogels Imprinted Against Glucose Glucose Fructose Insoluble Selective Binding Hydrophilic Mechanical Stability
  • Slide 9
  • Characterization of Arborescent Graft Polymers Robert M. Briber, Materials & Nuclear Engineering, U. of Maryland Mario Gauthier, University of Waterloo AFM micrograph of a film of 3 rd generation AGP molecules synthesized from 30k M w PS branches. Scaling of Rg with molecular weight of the form Rg~M with =0.25. This indicates that arborescent graft polymers become more dense with increasing size (molecular weight). This behavior must be self-limiting when the red line intersects the line defining the hard sphere limit. see: S. Choi, R.M. Briber, B.J. Bauer, D.-W. Liu, M. Gauthier Macromolecules, 33(17), 6495-6501(2000)
  • Slide 10
  • Polymer Chain Conformation in Ultrathin Films R.M. Briber, Materials and Nuclear Engineering, U of Maryland S.K. Kumar, Penn State U. Experimental Sample Geometry Results: Rg in plane of film is constant! Rg in thickness direction is constrained by film dimensions. Rg in plane of film remains constant with decreasing film thickness. see: R.L. Jones, S.K. Kumar, D.L. Ho, R.M. Briber, T.P. Russell, Nature, 400, 146(1999)
  • Slide 11
  • Characterization of Arborescent Graft Polymers Robert M. Briber, Materials & Nuclear Engineering, U. of Maryland Mario Gauthier, University of Waterloo Objective: Characterize the behavior of arborescent graft polymers in solutions and in blends with linear polymers Arborescent graft polymers are new molecules with an unusual chain architecture. The goal is to use small angle neutron scattering to measure the size and shape in solutions and blends. The characterization of the size, shape and density profile of arborescent graft polymers will provide insight useful for tailoring them to meet end use requirements as unimolecular micelles, drug delivery vehicles and flow modifiers. Approach: Use small angle neutron scattering to measure Rg and (r) in solutions and blends. Deuterated solvents and linear polymers are used to provide neutron contrast.
  • Slide 12
  • Block Copolymers:Functional Nanostructure Templates Peter Kofinas, Chemical Engineering l Microphase separation due to block incompatibility or crystallization l Templates for synthesis of metal and metal oxide nanoparticles B-Block A-Block Chemical Link C-Block B-BlockA-Block Chemical Link 0 - 21 %21 - 34 % 34 - 38 %38 - 50 % Increasing Volume Fraction of Minority component
  • Slide 13
  • Ring Opening Metathesis Polymerization (ROMP) Peter Kofinas NSF CTS-981601 Synthesis of [Norbornene] 400 [Norbornene-dicarboxylic acid] 50 Synthesis of [Norbornene] n [Norbornene-cobalt-amido] m
  • Slide 14
  • Magnetic Nanoparticles Within Block Copolymers Peter Kofinas NSF CTS-981601 CoFe 2 O 4 Co 3 O 4 15nm
  • Slide 15
  • Magnetic Nanoparticle Formation Peter Kofinas NSF CTS-981601 Cobalt Oxide CoFe 2 O 4 nanoparticles Cobalt Oxide nanoparticles
  • Slide 16
  • SANS and Neutron Reflectivity Peter Kofinas, Dept of Chemical Engineering Robert Briber, Dept of Materials & Nuclear Engineering Funding: NSF MRSEC DMR-008008 l Magnetic neutron scattering to separate and compare o ordering of nanoparticles o microphase separated block copolymer morphology l Obtain information about state of magnetic spin in sample l Follow microstructure development with temperature l Long range order in thin films
  • Slide 17
  • Polymeric Nanoscale Solid State Batteries Peter Kofinas ONR N00140010039 Objective: Synthesize a nanoscale all solid-state polymer battery Approach: Use a triblock copolymer where the three blocks are the anode, electrolyte and cathode of the battery Accomplishments: Synthesis and characterization of monomers. Polymerization of lithium block as the anode. Impact: All-Solid State Battery advantages: o No leackage of toxic liquid electrolyte o Production of thin films processed as Coatings Sheets Anode CathodeSolid ABlockB C Electrolyte(Oxidation) (Reduction) A B C TMS O O O O O O O O n CH 2 N t-Bu t-Bu CH 2 N Co n m
  • Slide 18
  • Piezoelectric ZnO Nanoclusters Within Block Copolymers Agis Iliadis, Dept of Electrical and Computer Engineering Peter Kofinas, Dept of Chemical Engineering Funding: NSF EECS

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