Monday, January 22, 2018

3:00pm - 4:00pm

Mechanics and Chemistry in Designing Polymers

Abstract

The coupling of mechanics and chemistry is an emerging field leading to innovative material design. This talk will cover two projects within my group, one towards utilizing mechanochemistry in polymers and composites, the other towards tailoring bulk polymers formed from assemblies of single chain polymer nanoparticles (SCPN). Topic 1: Polymer and interface multifunctionality can be designed through the incorporation of chemical groups termed "mechanophores" that have a specific chemical transformation in response to applied force. Mechanophores have been developed that change color, emit light, alter polymer chain contour length, and trigger crosslinking. However, incorporating these force-driven molecules to create stress-driven functions in bulk materials can be tricky. We use a combination of computational, theoretical, and experimental approaches to understand how stress on the bulk scale is converted to mechanophore-scale force to then modify the polymer. Topic 2: SCPN are formed from intra-chain cross-linking of a single polymer chain. These units have potential as the building blocks of polymers where the properties are controlled by the highly tailorable SCPN structure rather than just by the material chemistry. We utilize both molecular dynamics simulations and experiments to investigate the mechanical behavior of a SCPN assemblies as a function of degree of polymerization and cross-linking.

Biography

Meredith Silberstein is an Assistant Professor and Mills Family Faculty Fellow in the Sibley School of Mechanical & Aerospace Engineering at Cornell University. She received her PhD in June 2011 from the MIT Department of Mechanical Engineering with a major in solid mechanics and a minor in energy. Afterward, she served as a postdoctoral fellow at the Beckman Institute at the University of Illinois Urbana-Champaign, investigating mechanochemically active materials. In 2013 she received the Haythornthwaite Research Initiation Grant from ASME Applied Mechanics Division. In 2017 she received the NSF CAREER award. Meredith Silberstein's Mechanics for Materials Design (MMD) Lab is devoted to using mechanical experiments and modeling methods in material design, with particular focus on multifunctional, active, and polymeric materials.