Current limitations in the preparation and utilization of photoresponsive moieties have inhibited the development of enabling technologies that use the advantages of light-responsive polymers in new ways. The research objective of this award is to develop polymeric materials that have new photoresponsive properties because of the inclusion of photolabile groups, such as the o-nitrobenzylester (NBE) moiety. The central hypothesis of this research is that rational design of polymers with photolabile groups will enable photochemical control over the non-covalent intermolecular forces governed by hydrophobicity and charge-charge interactions. This research will focus on three classes of new light-responsive polymeric systems: 1) new block copolymers designed to switch from hydrophobic to hydrophilic, 2) layer-by-layer (LbL) polyelectrolyte films that switch interlayer electrostatic forces from attractive to repulsive, and 3) surface-bound polymeric coatings that switch the sign of the zeta potential. The proposed work is significant because it combines polymer synthesis and photochemistry to control intermolecular forces, resulting in new approaches to control matter with light. Expected outcomes of this research include polymers that photo-assemble into and disassemble from micelles, LbL films that are photopatternable in three dimensions, and coatings that enable photochemical control over electroosmotic fluid flow and static charging. These outcomes have potential applications in: 1) photochemically-labile carriers for targeted delivery, 2) all-aqueous photolithography, 3) photo-controlled microfluidic devices, and 4) photochemical control over the static charging of insulators.
NON-TECHNICAL SUMMARY
Materials that respond to light have major technological importance, with applications ranging from human health (e.g. imaging agents and photochemical delivery of therapeutic agents) to microprocessor fabrication (e.g. high-resolution patterning of polymers in photolithography). The proposed interdisciplinary research will develop polymers that respond to light in new ways with both fundamental and applied implications. The proposed work also integrates this research with education through two new programs: 1) encouraging STEM careers by involving a local community college in scientific research; 2) a high school science fair mentoring program.
