University of Connecticut |
Polymer Program SeminarSynthesis and Applications of Model Block Copolymers Friday, February 8, 2008 11:00 am , IMS Room 20 Anionic polymerization affords polymeric materials with the highest control of molecular weight distribution, chain architecture, and chemical composition available by synthetic methods. In that sense, it is the closest we can get to mimicking biological materials. Block copolymers produced by this method will self-assemble in both solution and in the melt. This allows a bottom-up approach to materials that order at the nanometer scale. Three applications of these materials will be discussed: 1. Polymer based vesicles termed “polymersomes”: These spherical “balloon like” materials are spontaneously formed from block copolymers of the correct volume fraction. Our work has focused on improving the methods for the production of polymersomes and their application to biological systems with the intent of drug and gene delivery. 2. Functionalization of block copolymers: This process has been used to mimic the catalytic function of a natural protein, silicatein a. The silicatein a protein allows the organism to form silica at ambient temperatures and pH. Starting with the known structure of the protein, we assembled a block copolymer mimicking the chemical groups shown to be central to the catalytic function of the protein. This material indeed shows catalysis of silica precursors to silica at biological conditions. 3. Utilizing self-assembly of block copolymers in the melt to form nanoscale structures: These structures serve as a lithographic mask to pattern large surfaces at the nanometer scale. The process is quick and affords densities of 1011 features per square centimeter. A description of the process and our work to control the ordering of the masks, as well as applications of this process, will be discussed.
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