Miscibility of graphene and poly(methyl methacrylate) (PMMA): molecular dynamics and dissipative particle dynamics simulations

Abstract

Nanomaterial–polymer nanocomposite materials have attracted much interest due to their advantageous polymer properties and ability to improve the properties of nanomaterials. The distribution of nanomaterials in polymer materials strongly affects the enhancement of these properties. If the nanomaterials aggregate, this enhancement diminishes. In this study, a dissipative particle dynamics (DPD) simulation is used to investigate the structure of graphene–poly(methyl methacrylate) (PMMA) with different volume fractions (1 : 9, 1 : 14.29, 1 : 24 and 1 : 49) of graphene. As the immiscibility of graphene in the PMMA polymer induces phase separation, the repulsive parameters between PMMA and graphene were modified to represent different degrees of functionalization to find what repulsive parameter value will cause functionalized graphene to disperse in the PMMA polymer. We found that when the volume fraction of graphene is higher, the graphene needs to be functionalized more to achieve dispersion. In addition, different concentrations of functionalized graphene (30%, 50%, 70%, 90% and 95%) are studied, with results showing that if the graphene is more compact, a higher concentration of functionalized graphene is needed to disperse the graphene in the PMMA polymer system.