Bead Spring Simulations of Polymer Nanofiller Composites to Study Equilibrium and Stress-Strain Response Properties

It has long been recognized that the introduction of nanofillers within a polymer matrix can greatly enhance its mechanical properties including stiffness, tensile strength, and impact resistance. Advances in controlling the surface chemistry of filler particles have led to greater customization options for polymer chemists. Despite such technological achievements, our basic understanding of polymer-filler interactions at the atomic level and its effects on the structural, mechanical, visco-elastic, and transport properties remain poor. Given the complex, multiscale nature of the problem a range of modeling tools can be insightfully used, including classical molecular dynamics (MD) at the all-atomistic or a coarse-grained level, dissipative particle dynamics, and finite-elements simulations using a constitutive materials model. In this work, we perform Kremer-Grest type bead-spring MD simulations of systems comprising nanofiller particles of effective size several tens of nanometers and explore equilibrium structure, polymer and filler dynamics, and stress-strain response, and attempt to correlate these properties to chain entanglements, polymer-filler interaction, and different states of filler aggregation.