Impact of hydrogen bonding interactions on graft-matrix wetting and structure in polymer nanocomposites

Properties of polymer nanocomposites (PNCs) are linked to their morphology which is dictated by the dispersion/aggregated state of nanoparticles in a polymer matrix. Grafting polymeric ligands onto the nanoparticle surface offers a greater control over morphology by allowing for tuning of effective interactions between graft and matrix polymers. One way to tailor interactions between graft and matrix chemistries is by the introduction of inter-molecular hydrogen bonds between graft and matrix polymers. In this talk, we present our work on the development of a coarse-grained (CG) model that allows us to capture hydrogen bonding type directional and specific interactions between graft and matrix polymers. Using this CG model, we run molecular dynamics (MD) simulations to elucidate the effect of these directional and specific interactions on the PNC morphology by comparing grafted layer wetting, graft and matrix chain conformations and free volume for each graft monomer between PNCs with isotropic graft-matrix interaction and PNCs with hydrogen bonding type graft-matrix interaction. We explore effects over a large design space comprising of grafting density, polymer flexibility, and strengths of isotropic graft-matrix attraction and hydrogen bonding interaction.