Challenges and Opportunities of Polymer Mechanochemistry

Polymer mechanochemistry is an emerging field at the interface of chemistry, materials science, physics and engineering. It aims at understanding and exploiting unique reactivities of stretched polymer chains. Macromolecules or their segments become stretched in bulk polymers under mechanical loads or when polymer solutions are sonicated or flow rapidly through abrupt contractions. Increasing amount of empirical data suggest that mechanochemical phenomena are widespread wherever polymers are used. In the past decade, empirical mechanochemistry has progressed enormously, from studying fragmentations of commodity polymers by simple backbone homolysis to demonstrations of self-strengthening and stress-reporting materials and mechanochemical cascades using purposefully designed monomers. Progress in developing the conceptual foundation of mechanochemistry has been more limited. I’ll discuss this progress using specific examples to illustrate the opportunities both for fundamental studies of polymer behavior and for potential applications. I’ll also describe the outstanding challenges facing polymer mechanochemistry, particularly in developing conceptual frameworks within which to rationalize, systematize and generalize empirical mechanochemical observations. I’ll conclude by suggesting 5 important scientific problems that can be advanced by exploiting polymer mechanochemistry.