MSE Ph.D. Defense – Chaowei Feng
MSE Ph.D. Defense – Chaowei Feng
Date: Friday, March 27, 2015
Time: 10:00 AM - 12:00 PM
Location: MoSE (Molecular Science & Engineering building) 3201A
Dr. Zhiqun Lin (MSE, Advisor)
Dr. John Reynolds (MSE/CHEM)
Dr. Anselm C. Griffin (MSE)
Dr. Vladimir V Tsukruk (MSE)
Dr. Seth Marder (Chem/MSE)
Title: RATIONAL DESIGN AND SYNTHESIS OF FUNCTIONAL POLYMERS WITH COMPLEX ARCHITECTURES BY LIVING/CONTROLLED POLYMERIZATION
Significant progress has been made in the field of living/controlled polymerizations over the past decades. The advance in living/controlled polymerizations has enabled the design and tailoring of structurally well-defined macromolecules with complex architectures. Polymers with complex molecular architectures often exhibit properties that are distinct from their linear counterparts. This dissertation aims to exploit the unique properties of rationally designed complex polymer structures to address the challenges related to the preparation of polymeric and hybrid nanostructures, as well as to explore and fundamentally understand the morphology or properties of new macromolecular architecture.
The studies presented in this dissertation addressed the challenges (e.g., poor size uniformity, limited accessible compositions) in the formation of polymeric or hybrid nanostructured materials based on the self-assembled polymer micelle approach via rational design of complex spherical star polymer architectures with tailor-made compositions and functionalities through living/controlled polymerizations, as well as investigated the morphology and self-assembly behavior of a newly designed cyclic brush copolymer grafted with P3HT as the side chains. Specifically, the uniqueness of this study can be summarized through the following novel and critical findings:
1. Uniform core-shell polymer nanoparticles can be formed by photo-crosslinking the shell layer of a monodisperse core-shell star block copolymer with azide moieties attached in the shell block. The dimensions of nanoparticles including the core size and the overall diameter are governed by the molecular weights of constituent blocks (i.e. inner and shell block) in the core-shell star diblock copolymer template.
2. Uniform hollow polymer nanoparticles with retained structural integrity can be produced by etching the degradable inner core of the unimolecular shell-crosslinked nanoparticles.
3. Organo-silica hybrid nanostructures can be crafted if the sol-gel chemistry of trimethylsilyl groups attached to the star polymer templates is employed as the crosslinking mechanism. Nanoparticles were yielded when the trimethylsilyl groups were incorporated in the inner block of star polymers, while nanocapsules with an interior cavity were produced when trimethylsilyl moieties were integrated in the shell block.
4. The novel cyclic brush copolymer composed of PEG as the backbone and P3HT as the side chains self-assembled into an interesting and unique macro-ring morphology in selective solvent.
The novel and robust star macromolecular templating strategy developed in this study will open the access to a wide range of structurally and functionally well-defined polymeric and hybrid nanostructured materials with tailor-made compositions and shapes. The findings presented in the study will provide a fundamental insight and practical strategy for rational design of polymers with complex macromolecular architectures via living/controlled polymerizations.
- Workflow Status:Published
- Created By:Danielle Ramirez
- Modified By:Fletcher Moore