Simulating chemical transport in functionalized polymer-particle composites

Improved chemical resistance of polymer-based coatings remains a significant challenge for many defense applications and technologies. In particular, composites with high concentrations of large, micron-size particles present a complex microstructural landscape of competing processes which influence the transport of penetrant molecules.  In this talk we report on molecular dynamics calculations designed to model particle surfaces that have been modified by the addition of functional groups. The effects of the functionalized surfaces on the surrounding polymer binder and the diffusive transport of penetrant molecules is examined for different chemistries. We directly calculate penetrant diffusion coefficients and polymer-penetrant properties within an identifiable interfacial region in the composite, and quantitatively compare with simulations of transport in the bulk systems.