UNIVERSITY OF ROCHESTER
This research involves the design, synthesis, and study of network polymers containing highly selective, multiple hydrogen-bonding side-groups. The major research goal is to understand how reversible binding affects the materials rate-of-strain and mass transport kinetics. Shape memory polymers (SMPs) will be developed that 1) are transparent to light at all processing temperatures, 2) exhibit amorphous or rubbery low-temperature states, and 3) enable precise tuning of shape recovery temperatures and rates. Preliminary studies have shown that lightly crosslinked elastomers containing reversibly associating side-groups exhibit shape-memory effects with a unique temperature-dependent shape-recovery. Planned research builds on these findings through the synthesis of well-defined elastomers involving uncrosslinked (linear) polymer precursors. Living free radical polymerization of poly(acrylates) will be performed to systematically vary architectural parameters including a) covalent crosslink density, b) associating side-group content, c) side-group spacer length, and d) the type and strength of H-bonding side-group. Synthesized polymers and networks will be studied in solution and in the melt to elucidate mechanistic details that influence shape memory responses. Research will pave the way to develop new features including two-stage shape responses, light and magnetic field triggered responses, and recyclable shape-memory materials. Research will also examine how reversible hydrogen-bonding affect mass transport. Diffusion of small molecules through synthesized networks will be studied using a custom-built permeation apparatus as well as multiphoton fluorescence recovery after photobleaching (MP-FRAP) techniques. The research plan provides a springboard for the PI to investigate biomedical devices including intraocular lenses, spinal disk prosthetics, and drug delivery platforms.