Date: Tuesday, March 1, 2016
Time: 11:00 am
Speaker: Will Dichtel, Cornell University
Title: Noncovalent Binding and Dynamic Bonding in Crosslinked Polymer Networks
Location: 67-3111 Chemla Room
Crosslinked polymers with permanent porosity provide empty spaces that facilitate valuable functions, including host-guest chemistry. For example, insoluble polymers of β-cyclodextrin (β-CD), an inexpensive, sustainably produced macrocycle of glucose, are of interest to remove micropollutants from water by means of adsorption. Previous cross-linked β-CD polymers have low surface areas and poor adsorbent performance compared to conventional activated carbons (ACs). Our high surface area β-CD polymer rapidly sequesters organic micropollutants with adsorption rate constants 15-200 times greater than ACs and nonporous β CD adsorbents and the outperformed a leading AC for the instant removal of a complex mixture of organic micropollutants at environmentally relevant concentrations. In a separate effort, we have explored dynamic covalent bond formation and exchange to impart repair and reprocessing capabilities to polyurethane networks, whose stress relaxation processes at elevated temperatures appear to be mechanically activated.