Ideas for Creating Impact Resistant Polymeric Materials by Tuning Molecular Topology

Biological materials employ diverse strategies for maintaining robustness against extreme mechanical environments, which often originate from clever molecular interfaces and microstructures. In this talk, I will summarize recent advances in computational design of new polymeric materials that make use of nanoscale topologies that result in improved mechanical properties. I will first present physics-based and data-driven approaches that we developed to describe molecular and mesoscale mechanics of polymer thin films and nanocomposites. Following this, I will present three distinct strategies for achieving impact tolerance in soft materials. The first strategy takes inspiration from helicoidal, imbricated Bouligand microstructures found in natural shells and armor materials, which results in superior impact response. The second strategy involves the use of star polymers and polymer grafted nanoparticles to improve diametric mechanical properties such as modulus and toughness,as well as the time-dependence of the mechanical response. The final strategy involves creating nanoparticle interfaces that take inspiration from catch bonds in biological adhesion proteins, which results in molecular seat-belt type interfaces that self-strengthen at high strain rates, in a way similar to shear-thickening fluids. I will conclude with some thoughts on how to translate these theoretical findings to new material concepts that could be explored further with synergistic experiments and simulations.