This research capitalizes on the robust nature of reversible bond formation between diols and boronic acids for the preparation and investigation of self-assembled and responsive macromolecular material. Two particular systems will be investigated: (1)stimuli-responsive block copolymer assemblies and (2)dynamic covalent self-assembled materials. In the first system, diblock copolymers with a permanently hydrophilic block (e.g.,poly(ethylene glycol) or polyacrylamide) and a responsibe boronic acid containing acrylamido or styrenic block will be prepared by combination of controlled radical polymerization and other efficient postpolymerization transformations. In the absence of diol and at pH NON-TECHNICAL SUMMARY: By preparing nanoscale objects that undergo rupture and reconstruction when exposed to changes in their local environment, fundamental insight can be gained into many of the mechanisms governing the controlled delivery of therapeutics and the behavior of new self-healing and adaptive materials. Because these studies require a diverse set of skills from materials science, chemistry, and engineering, students and junior scientists involved in this research are provided with a truly interdisciplinary set of skills that can enhance the workforce necessary to accelerate development of new advanced and sepciality materials market. An outreach component of the research is desinged to directly address many of the mandates of the American Competitiveness Initiative by establishing collaborations with local community colleges and independent K-12 school districts to facilitate the inclusion of underrepresented minority students for internship positions within the Department of Chemistry at Southern Methodist University. Intellectual merit: This project was designed to capitalize on a straightforward reaction to obtain polymeric materials with responsive behavior that allowed the polymers to change their properties depending on the conditions of the surrounding environment. Instead of the static/constant properties most materials demonstrate, this approach allowed us to prepare materials that demonstrated adaptive behavior more commonly associated with living systems. To obtain these polymers, we developed a variety of new synthetic techniques that have subsequently been adopted by the polymer chemistry community to prepare a variety of materials for many applications. To demonstrate the potential utility and impact of this concept, two particular systems were considered: (A) stimuli-responsive block copolymer assemblies and (B) dynamic covalent macromolecular materials. The first system relied on polarity/solubility transitions of block copolymers in water, which occurs upon reactions with sugars. The second area involved the investigation of polymer assemblies with complex macromolecular topologies constructed via reversible bonds. The new materials created as a result of this support may hold promise for the glucose-responsive release of insulin for the treatment of diabetes and for the creation of self-healing polymeric materials. Broader impacts: Undergraduate, graduate, and community college students and postdoctoral fellows were trained during this project, many of whom have moved onto positions in industry, academia, and medical school and law school. International collaborations were developed, and the results of this research have been disseminated in the top journals in our field.Project Report
