Polymer nanocomposites make up a large variety of applications and are generally widely adapted for their appealing combination of properties. For example, elastomeric nanocomposites - rubber reinforced by the introduction of nanoparticles - exhibit remarkable mechanical toughness, as well as stretchability. Despite their wide adaption for almost a century, a complete mechanistic understanding of the origins of toughness has escaped the scientific community. At the David S. Simmons lab and with the support of a DOE grant, I study the stress response of elastomeric nanocomposites during stretching using molecular simulations. A better understanding of these materials could open to door to major technological advances driven by improved material properties.

Copolymers combine two monomers in a single chain and can feature desirable properties, depending on several factors. The effect of the specific sequence on properties can be quite dramatic and difficult to predict apriori. A better understanding of sequence specific effects on properties promises to improve properties of preexisting applications and enable adaption of new and improved materials. Given the large landscape of parameters (stereo and regio regularity, composition, sequence, etc.), screening potential desirable systems is tedious and prohibitive.

When combined with studies of the glass transition, this problem is further exacerbated. The glass transition temperature Tg divides two phases, the disordered liquid from the disordered solid, which feature a wide difference in properties. Depending on the application, it may be advantageous to be above or below Tg. In addition, some copolymers feature desirable properties that can become more applicable if can be combined with glassy dynamics.

Using molecular simulations at the David S. Simmons lab of the glass transition of sequence specific copolymers, we are actively exploring this landscape. This thrust will lead to a better understanding of the effect of sequence specificity on the glass transition and to new generation materials with a desirable property set.