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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