Influence of polymer matrix on polymer/graphene oxide nanocomposite intrinsic properties

Electrically conductive polymer nanocomposite films comprising reduced graphene oxide (rGO) have been prepared using aqueous emulsion-based techniques with a specific focus on the effects of the polymer matrix. Polymer matrices with glass transition temperatures in a suitable range were selected such that film formation can occur at ambient temperature via drop-casting of the as-obtained nanocomposite latexes. The monomers methyl methacrylate (MMA), benzyl methacrylate (BzMA), and styrene (St) were each copolymerized with n-butyl acrylate (nBA) using radical polymerization implemented as miniemulsion polymerization or soap-free emulsion polymerization. Thermal annealing of the films converted GO to rGO, thus imparting electrical conductivity. In agreement with theoretical calculations related to the propensity of GO sheets to operate as Pickering stabilizers based on polarity and interfacial tension, nanocomposites with higher electrical conductivity resulted for monomers of lower polarity such as nBA/St and nBA/BzMA compared to the more polar system nBA/MMA. Incorporation of GO resulted in higher Young’s modulus and more brittle materials regardless of the polymer matrix. The results demonstrate that relatively subtle changes in the nature of the polymer matrix can have significant effects on nanocomposite properties.