Annual reportGrant No. PIIF-GA-2009-252943

Architectures, morphologies and applications of

organic/inorganic nanomaterials containing polyhedral

oligomeric silsesquioxanes

(Acronym: AMAAOOINCPOS)

By Weian Zhang

University of Leeds

Short summary

During the past two years, we have synthesized a series of functionalized polyhedral

oligmeric silsiquioxane (POSS) molecules, which have been used as monomers, click

chemistry agent and initiators. These functionalized POSS molecules have been used

to produce POSS-containing polymer hybrids including block copolymers, alternating

copolymers and telechelic copolymers. We have further studied the self-assembly

behavior of POSS-containing block copolymers and obtained interesting assembled

morphologies. We have also extended the hybrid polymers to other kinds of

inorganic/organic system, metal-containing hybrid polymers, since these metal

components can offer the functionality for hybrid polymers. We have prepared

ruthenium- and rhodium-containing hybrid polymers, respectively. Dr. McGowan has

a rich experience in this field, and he published a lot of ruthenium and rhodium

compounds as anti-cancer drug and catalysts. Additionally, as an incoming research

fellow, I transferred my polymer knowledge and experience to Leeds, and have

developed and nurtured interdisciplinary research interests. I have also helped to build

up the international communications and collaborations between host university and

Chinese universities. I have invited academics from the University of Leeds to visit

Chinese universities, and present their work, and discuss some collaboration with

Chinese researchers.

Detailed description of the completed work:

1) Preparation of functionalized polyhedral oligmeric silsesquioxane (POSS):

We have prepared a series of functionalized POSS molecules which can be used as

monomers, initiators and “click chemistry” agents. For example, we synthesized

the POSS-containing monomer with a long side methylacrylate group (Figure 1),

which have been used to POSS-containing with high molecular weight.

Figure 1. Functionalized POSS molecules, POSS-containing methyl

methacrylate monomer (MA-POSS) and POSS-containing click chemistry agent.

2) Preparation of POSS-containing hybrid polymers with different topological

structures:

For example, we have synthesized amphiphilic hybrid block copolymers,

poly(methacrylisobutyl-POSS)-b-poly(2-((dimethylamino)ethylmethacrylate)

(P(MA-POSS)-b-PDAEMA) using ATRP (Figure 2). We first prepared

alternating POSS-containing copolymers. POSS-containing poly(tert-butyl

acrylate) (Glu-PtBA-POSS5) with a penta-telechelic structure was prepared by

the combination of ATRP and “click chemistry”. The penta-telechelic Glu-

PtBA-POSS5 was further hydrolyzed into POSS-containing penta-telechelic

poly(acrylic acid) (Glu-PAA-POSS5) using trifluoroacetic acid. (Figure 3)

Figure 2. POSS-containing hybrid copolymers, block copolymers and

alternating copolymers.

Figure 3. Synthesis of penta-telechelic POSS-PAA by a combination of ATRP

and “Click chemistry”

3) Self-assembly of POSS-containing hybrid amphiphilic copolymers

In past reports on the self-assembly of POSS-containing hybrid polymers, the self-

assembly morphologies were mostly studied in bulk. For example, a lamellar self-

assembly nanostructure can be obtained from POSS-containing random or block

copolymers. There are few reports on the self-assembly behavior of POSS-

containing hybrid polymers in solution. In our present work, we studied a series of

POSS-containing amphiphilic copolymers in solution. For example, P(MA-

POSS)-b-PMAA block copolymers can self-assemble into string like shapes in

aqueous solution (Figure 4a). We also obtained the assembled spherical aggregates

from P(MA-POSS)-b-PDAEMA block copolymers in aqueous solution (Figure

4b). Interestingly, the giant assembled capsules were obtained from the self-

assembly Glu-PAA-POSS5 in aqueous solution (Figure 5). From its enlarged

image, the surface of the Glu-PAA-POSS5 is relatively homogeneous, except for

several dark dots. This indicates that POSS does not form some bigger aggregation

in the membrane of the capsule. Thus, this is typical capsule obtained from self-

assembly of hybrid copolymers, which is a similar to the conventional one

prepared by LbL assembly technique. Correspondingly, a schematic illustration is

shown in Scheme 1.

Figure 4. AFM image of self-assembly aggregates of block copolymers in

water, P(MA-POSS)-b-PMAA (a), and P(MA-POSS)-b-PDAEMA (b).

Figure 5. TEM image of POSS-containing star-shaped hybrid

poly(acrylic acid) (Glu-PAA-POSS5) aggregates in water.

Scheme 1. Self-assembly process of penta-telechelic Glu-PAA-POSS5 in water.

The metal-containing hybrid polymer

During the project, we extended our work to other kinds of inorganic/organic hybrid

copolymers. We have synthesized hybrid poly(ethylene oxide) based on ruthenium

(Ru) and rhodium (Rh), which are well-known catalysts. Recently, Dr. McGowan’s

research group has developed these kinds of metal compounds as anti-cancer drugs.

Here, we tried to prepare novel anti-cancer drugs with a high efficiency via the

combination of these special metals and polymers. Additionally, we also prepared

Ru/Rh-containing homo-poly(4-vinylpyridine) (P4VP) and block copolymers

poly(ethylene oxide)-block-poly(4-vinylpyridine) (PEO-b-P4VP) using RAFT

2 µm

1 µm

polymerization, respectively, and their catalyzed capability will be studied in the

future.

Figure 6. Synthesis of hybrid poly(ethylene oxide) based on ruthenium (Ru).

Mobility events and conferences

As an incoming Marie Curie Research fellow, I transferred my polymer knowledge

and experience to Leeds here, and discussed my work with my colleagues, and we

have developed some interdisciplinary research interests. I also helped to build up the

international communications and collaborations between Leeds University and

Chinese universities. I have invited them to visit the Chinese universities, and

presented their work there, and discuss some collaboration with Chinese researchers.

The events and conferences were listed as following:

Leeds

Dr. Patrick McGowan, Dr. Dejian Zhou and Dr. Rongjun Chen. Although my

research interest is related to polymer science, I have some collaboration work with

Dr. Patrick McGowan, Dr. Rongjun Chen and Dr. Dejian Zhou. Dr. Patrick McGowan

is my host in UK, and we have developed a novel research interest on ruthenium- and

rhodium-containing hybrid polymers, which are promising for catalysts and anti-

cancer drug. Additionally, Dr. Rongjun Chen and Dr. Dejian Zhou are working on

drug delivery system, and we have some collaboration works on drug release system

based on polymer/quantum dots.

Warwick polymer conference

The Polymer Conference July 9th 2012, at University of Warwick. I presented my

research work in that conference and discussed with many polymer guys from the

world.

Newcastle polymer symposium

I presented my research work in that conference and discussed some collaboration

with Dr. David Huston who is a lecturer in polymer science at Newcastle University.

Bradford polymer symposium

I discussed my work with Prof. Steven Armes, (University of Sheffield) and gave him

an invitation to China.

Germany, Europe

University of Bayreuth, Germany

I visited Prof. Axel Mueller’s group at Bayreuth, Germany and attended the

symposium “Self-Organized Polymer and Hybrid Structures”, on July 20, 2012, and

all the speakers are almost top scientists in the world.

China

East China University of Science and Technology (ECUST), Shanghai. I invited Dr.

McGowan to visit ECUST and gave a lecture there. I also arranged him to talk with

my colleagues.

Zhejiang University

Conference ： The 2011 International Symposium on Functional Polymers and

Nanomedicine at Zhejiang University Hangzhou, China, May 15-18, 2011. Dr. Patrick McGowan, Dr. Dejian Zhou, Dr. Rongjun Chen and I had attended this

conference, and I introduced a lot of my Chinese researchers to my Leeds colleagues.

Other Chinese top universities including Shanghai Jiaotong University and University

of Science and Technology of China (USTC)

Publications

1. One paper entitled “A giant capsule from self-assembly of the penta-telechelic

hybrid poly(acrylic acid) based on polyhedral oligomeric silsesquioxane (POSS)”

under preparation.

2. Another paper entitled “a novel anti-cancer drug based on rhodium (Rh)-

containing hybrid poly(ethylene oxide) (PEO)” under preparation.

3. “Architecture and Self-assembly of Telechelic Organic/Inorganic Hybrid

Polymers Containing Polyhedral Oligomeric Silsesquioxane (POSS)”, Warick

polymer conference

4. “Preparation and self-assembly of hybrid polymers containing polyhedral oligomeric silsesquioxane (POSS)”, Zhejiang university conference