Georgia Institute of Technology Materials Science and Engineering

Committee Members:

Prof. Seung Soon Jang, Advisor, MSE

Prof. Meisha Shofner, MSE

Prof. Blair Brettmann, ChBE, MSE

"Temperature-Dependent Conductivity in Graphene-Polymer Nanocomposite: Molecular Modeling Approach"

Abstract:

We investigated a graphene-polymer nanocomposite system using MD simulation method to analyze structural transitions between 298K and 373K which are observed through electrical conductivity measurement in experiment. To accomplish this, we prepared graphene-polymer nanocomposite model systems consisting of xanthan gum, Pluronic F127, and CTAB models. The equilibrated structures were obtained at 298K and 373 K using annealing procedure. In particular, we characterized the graphene-graphene contacts in the model systems using the pair correlation of graphene–graphene pair at 298 K and 373 K. It was found that the contributions of three different graphene–graphene contacts such as edge-to-edge, edge-to-plane, and plane-to-plane contacts are significantly greater at 373 K than at 298 K. We analyzed the role of each molecular components in these structural transitions of the nanocomposite systems using pair correlations of graphene–molecule pairs. It was found that xanthan gum plays a crucial role in the structural transitions between 298K and 373K. Furthermore, we evaluated the electrical conductivity of graphene-polymer nanocomposite model system using DFT-based non-equilibrium Green function approach.