(338b) Effect of Polydispersity in Grafts and Matrix on the Morphology of Polymer Grafted Nanoparticle Filled Polymer Nanocomposites

Polymer nanocomposites are a class of materials that consist of a polymer matrix embedded with nanoscale fillers or additives that enhance the inherent properties of the matrix polymer. To engineer polymer nanocomposites for specific applications with target macroscopic properties (e.g. photovoltaics, photonics, automobile parts) it is important to have design rules that relate molecular features to equilibrium morphology of the composite. In this poster we will present our recent theory and simulation work on composites containing polymer grafted nanoparticles in a chemically identical polymer matrix, showing how polydispersity in graft and matrix polymers affects morphology of the polymer nanocomposite. Polydisperse grafted polymers stabilize the dispersed morphology of homopolymer grafted nanoparticles in a chemically identical homopolymer matrix, due to improved wetting of the polydisperse grafted layer by the monodisperse matrix. In the case of polydisperse matrix polymers, modeled as a mixture of short and long chains, the short matrix chains preferentially wet the monodisperse grafted layer (at high grafting density) more than the long matrix chains. Despite the preferential wetting by the short than long chains, matrix length bidispersity does not significantly change the overall wetting of the grafted layer, and as a result does not alter the tendency for dispersion/aggregation of the grafted particles. Furthermore, graft length bidispersity is better than matrix length bidispersity for stabilizing dispersions of polymer grafted nanoparticles in a chemically identical polymer matrix.