This proposal outlines a 5 year plan centered on understanding how light-induced conformation changes in surface-bound polymer brushes influence surface, interfacial, and macroscopic properties in photochromic thin films. The three dimensional arrangement of photochromic moieties in extended polymer chains result in an increased density of functional groups at the surface that can be used to amplify the stimuli responsive nature of functional coatings. This proposal is aimed at synthesizing photochromic polymer brushes using surface initiated polymerization techniques that can be used to complete the following three research objectives: (1) Using light to control the colorimetric response of photochromic polymers through metal ion complexation. The reversible binding mechanism of photo-induced complexation that occurs when spiropyran containing polymers are irradiated in the presence of different metal ions will be elucidated and exploited to generate reversible ion sensors. (2) Investigating reversible, photo-switchable adhesion. The design of surfaces that undergo photo-induced phase separation will allow for surfaces that switch from adhesive to non-adhesive states. (3) Investigating photo-induced mechanical motion on the single molecule level. Light will be used to induce conformation changes between random coils and extended chains on surface of different free energy, leading to photo-induced mechanical motion.
NON-TECHNICAL SUMMARY:
The creation of functional surfaces with controlled interfacial properties using light as an external stimulus will have a major impact on a wide variety of scientific developments, such as sensors, microfluidic devices, controllable drug delivery, optical data storage, self-cleaning, antifogging and antifouling surfaces. Light as a stimulus can provide the ability to control sensor response remotely, with high speed and spatial precision. Measuring and quantifying the interfacial forces involved in photoresponsive polymer surfaces will help to elucidate the origins of adhesion in responsive materials. The understanding of polymers, especially in two-dimensional space, will be improved with the investigation of photo-induced motion at the molecular level. The technical nature of this project provides an interdisciplinary training experience to graduate and undergraduate students in polymer synthesis and thin film characterization. This training will provide students with the skill set necessary in addressing the future needs of polymer scientists. A significant outreach component of this proposal includes a ?summer camp? for ten high school teachers to be held at the University of Georgia is aimed at providing teachers with simple experiments involving polymer science to perform in their classrooms. The ultimate goal of this outreach project is to provide a large social and economic impact by influencing young students to pursue careers in science and engineering.
