Simulations of Filled Polymers on Multiple Length Scales

Abstract

We present simulation results of the effect of nanoscopic and micron-sized fillers on the structure, dynamics and mechanical properties of polymer melts and blends. At the smallest length scales, we use molecular dynamics simulations to study the effect of a single nano-filler on the structure and dynamics of the surrounding melt. We find a tendency for polymer chains to be elongated and flattened near the filler surface. Additionally, the simulations show that the dynamics of the polymers can be dramatically altered by the choice of polymer-filler interactions. We use time-dependent Ginzburg-Landau simulations to model the mesoscale phase-separation of an ultra-thin blend film in the presence of an immobilized filler particle. These simulations show the influence of filler particles on the mesoscale blend structure when one component of the blend preferentially wets the filler. Finally, we present some preliminary finite element calculations used to predict the effect of mesoscale structure on macroscopic ultrathin film mechanical properties.

Glass‐transition temperature behavior of alumina/PMMA nanocomposites

“…This is one of the biggest promises and challenges in nanocomposite engineering. The region of affected polymer was first hypothesized to be on the order of 2 to 9 nm,34 a result supported by most modeling,30 but, as we have seen in the paragraphs above, bulk mobility can be altered in thin films that are a 100 nanometers in thickness. Thus, the impact of the IZ may reach much farther into the bulk surrounding the nanoparticles, a result supported by recent nanocomposite work by Sternstein and Zhu40, 41 and Berriot et al42, 43…”

“…In addition, Schwab and Dhinojwala27 have recently shown that the free surface is characterized as having a lower activation energy and a narrower distribution of relaxation times than bulk PS. The extra mobility seen in these experiments is hypothesized to be mainly because of the segregation of chain ends at the free surface due to conformational entropy considerations,28, 29 a theory supported by computer modeling/simulation work30, 31 and neutron reflectivity experiments 32…”

Molecular Dynamics Simulation of Single Chain in the Vicinity of Nanoparticle

“…A considerable effort was devoted to understanding of viscoelastic properties of the materials. Phenomenological approach is not sufficient any longer, thus the studying of the materials on multiple length scales is useful [1].…”