This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
The ability to control functional group placement and polymer backbone structure in synthetic polymers is important for understanding fundamental structure property relationships as well as designing polymeric materials with important performance characteristics. The alternating copolymerization of substituted stilbenes and maleic anhydride or N-substituted maleimides will be studied as a new route to synthesize macromolecules with precise control of the placement and density of functional groups along the polymer backbone. The incorporation of the sterically crowded 1,2-diphenylethane units, in conjunction with the five member cyclic imide or anhydride units, results in structures that are anticipated to be considerably stiffened when compared to less constrained polymer chains. Synthetic targets of this research will include new sterically crowded polyanions and polycations with a regular variation of charge densities along the chain enabled by the alternating copolymerization of specifically designed and prepared functional stilbenes and maleimide comonomers. The consequences of the sterically constrained backbones and placement of functional groups on fundamental properties such as persistence length and solution rheological properties will be studied. Solid state NMR will be used to study the enchainment stereochemistry of the maleic anhydride and maleimide comonomers. The stiffened polyanions and polycations will be compared to polyzwitterionic structures with similar chain backbones. These new polyelectrolytes and polyzwitterions will be enchained into double hydrophilic block copolymers (DHBC) by controlled free radical polymerization techniques. These DHBC structures will be used to assist in establishing structure property relationships that govern the ?like-charge? attraction observed in DNA and more recently reported from the PI?s laboratory in a synthetic DHBC derived from a substituted stilbene-alt-maleic anhydride zwitterionic copolymer.
NON-TECHNICAL SUMMARY:
New precisely functionalized polymeric materials, based on easily scaleable and industrially practiced free radical polymerization chemistries have significant potential to have practical impact across a broad range of advanced technology frontiers. The fundamental research described in this proposal could foster a new polymer platform which has the potential to be used to produce new porous and high surface area network materials for hydrogen storage, new rigid polyelectrolytes for control of flow in aqueous fluids, new polyelectrolyte gels which could be applied in membranes, and new nano-particle stabilization agents. In addition the synthesis and study of new rod-coil aqueous block copolymers, derived from the new polymers of this study, will provide fundamental biomimetic information that can have impact in various biomedical applications such as therapeutic delivery. Active participation in the research project will require graduate students to master modern polymerization and synthetic chemistries and to interact with other scientists and engineers in a strong interdisciplinary mode in order to fully characterize and understand the properties of these new polymeric materials. The graduate students involved with this research will interact with industrial researchers in Virginia Tech polymer short courses and will mentor summer undergraduate students in the Macromolecules and Interfaces Institute?s NSF REU program. This specific training will be valuable for initiating viable careers for these researchers in a variety of industrial and academic areas important for sustaining and growing the nation?s science and technology enterprise.
