Nanofilled Polymer Melts

Background

Fillers have long been used in industry to improve the properties of polymer materials. "Nano-particles", such as gold particles, silica beads or silicate nano-particles, fullerenes and nanotubes, silsesquioxanes, and others influence material properties at molecular scales, and have the potential to be far more homogeneously distributed, and hence less material is needed for changes to bulk properties, keeping costs down. The eventual goal of this project is to understand the mechanism by which nano-fillers improve material properties, and thereby aid in measurement and development of new materials.

Approach

Simulation of filled polymer melts poses a particular challenge, since it is necessary to understand the system over a wide range of length scales. At the atomistic level, one needs to understand the effects of the interactions and geometry of nano-particles on the surrounding polymer, while at mesoscopic length scales, the distribution and dynamic clustering of the nano-particles becomes very important. Finally, from this information, one wants to understand the resulting changes in the overall mechanical properties. As a result, our research approaches the problem from 3 angles:
 
  • Molecular dynamics simulations of the atomistic properties yielding the dynamic and structural changes induced by a nanoscopic particle, on the surrounding melt.  This effort includes simulations of both symmetric and tube nanoparticles.
  • Mesoscale simulations via lattice Boltzmann, hydrodynamic lattice-gas, and dissipative particle dynamics techniques to probe the phase behavior and dynamic clustering of nano-particles
  • Using the configurations generated from meso-scale simulations, we study the mechanical properties using OOF (Object-Oriented Finite-Element), a general purpose tool designed in the CTCMS for studying mechanical properties.

    • Working Group:

  • Bruce Boghosian (Tufts)
  • Martin Chiang (NIST)
  • Jack Douglas (NIST)
  • Yeshitela Gebremichael (U. Maryland/Michigan)
  • Sharon Glotzer (U. Michigan)
  • Charles Han (NIST)
  • Steve Langer (NIST)
  • Nita Parekh (NIST)
  • Francis Starr (NIST)