Wednesday, November 10, 2010: 4:25 PM
252 A/B Room (Salt Palace Convention Center)
Polymer-nanoparticle mixtures have diverse industrial applications due to their unique properties. Many of these properties can be connected to the structural characteristics of the polymer in proximity to the nanoparticle surface. Examining properties at different length scales by atomistic simulation methods is hindered by limited conformational sampling. To overcome such limitations, we employ drastic connectivity-altering Monte Carlo techniques that have been shown to rigorously sample uncorrelated polymer configurations. Several algorithmic improvements of the methodology are discussed. Amorphous silica obtained by simulated annealing and molecular dynamics simulations serves as the precursor for models of nanoparticles of different sizes and geometric algorithms are used to calculate nanoparticle volumes and surface areas. Subsequent Monte Carlo simulations of nanoparticles in polyethylene polymer melts provide predictions for the bound layer, adsorbance and surface concentration. Detailed analysis of configurations reveals that nanopatricle size and curvature alter characteristics of bound layer to a significant extent. This effect is more pronounced for the smallest particles studied with diameter of two nanometers.