Professor Steve Craig

Professor Steve Craig
Department of Chemistry
Duke University

Getting Chemical Reactivity Into and Out of Polymer Networks

Polymer networks are the basis of materials used in automobile tires, biomedical implants, and building materials. These materials typically form a structural role, in which they bear an external load. That load can be coupled into mechanically responsive functional groups – mechanophores – that are embedded within the polymers. The external force then accelerates and/or biases the outcome of a desired chemical reaction, including reactions that are impossible to achieve through other mechanisms. The talk will begin with examples of this form of mechanochemistry in stoichiometric reactions as well as catalysis, including the fundamentals that underlie it. The remainder of the talk will focus on the use reactivity- guided molecular fracture pathways to rewrite traditional performance rules that dictate the limits of polymer network toughness and extensibility. The approach is to embed mechanophores that behave like conventional components of polymer strands and junctions unless and until they are at or near a molecular site of pending fracture. Depending on mechanophore placement and reactivity, polymer networks can be made an order of magnitude easier or an order of magnitude more difficult to tear. Because improvements can be realized without any other measurable change in network properties and require changes to only a few percent of the overall material composition, mechanophores open possibilities for rapid upgrading of current best-in- class materials with minimal retroengineering.

Steve Craig

Dr. Steve Craig received his undergraduate degrees (B.S. in Chemistry, A.B. in Math) from Duke in 1991. After a year at Cambridge (M. Phil.), he began doctoral work at Stanford, where he received his Ph.D. in 1997. Following his Ph.D., he took a position as a Research Chemist in DuPont Central Research until early 1999, when he moved to a postdoctoral position at The Scripps Research Institute. In 2000, he joined the Department of Chemistry at Duke, where he is now William T. Miller Professor of Chemistry. Since 2018, he is the Director of MONET, the Center for Molecularly Optimized Networks – an NSF Center for Chemical Innovation.

Hosted by Professor Timothy Lodge