(678d) Theory and Simulation Studies of Copolymer Functionalized Nanoparticles in Polymer Nanocomposites

Polymer nanocomposites consist of nanoscale additives, such as organic or inorganic nanoparticles, carbon nanotubes, and layered silicates, dispersed in a polymer matrix. Addition of these nanoscale fillers enhances the inherent physical properties of the polymer due to synergistic interactions between the matrix and the additives. Recently, significant interest has grown around the ability to create polymer nanocomposites with a controlled morphology that can be used for solar or photovoltaic (alternative energy), and electronics applications, where controlled spatial arrangement of nanoparticles mediated by a polymer matrix is extremely important. By functionalizing copolymers on to nanoparticle surfaces and systematically tuning the composition and chemistry of the grafted polymer, the molecular weight of the grafted polymer with respect to the matrix polymer, and placement of the grafted copolymers we can tailor the inter-particle interactions and precisely control the spatial organization of the particles in the polymer matrix. Most of the prior experimental and theoretical work in this area has been on homopolymer grafted particles at high brush-like grafting densities. We study systems of copolymer grafted nanoparticles at low grafting densities through an integrated theory and simulation approach consisting of Polymer Reference Interaction Site Model (PRISM) theory and Monte Carlo simulations. In this talk I will present the effect of various parameters, such as molecular weight and composition of the grafted polymer, molecular weight of matrix polymer, compatibility of the graft polymers and matrix polymers, and nanoparticle size on the conformations of the grafted and matrix polymers and thus the effective interactions between the functionalized nanoparticles in the matrix.