Comparison of the Emulsion Mixing and In Situ Polymerization Techniques for Synthesis of Water-Borne Reduced Graphene Oxide/Polymer Composites: Advantages and Drawbacks

Water-borne reduced graphene oxide (rGO)/polymer composites have been synthesized by emulsion mixing and in situ polymerization. The main challenge is to synthesize colloidally stable hybrid latexes that are able to produce composite films by water evaporation at standard atmospheric conditions for their possible application as electrically conductive coatings. The selected polymer system is composed from poly(methyl metacrylate/butyl acrylate) in 50/50 wt% ratio in order to obtain glass transition temperature of the final film lower than the room temperature. The polymer is joined with rGO stable dispersions, which are prepared by reduction of GO in the presence of polyvynil pyrrolidone (PVP). The latex blends are composed of weakly bonded rGO platelets with polymer particles by the presence of PVP, whereas the covalent bonds between the polymers and the rGO in the in situ hybrid latexes are established. Both procedures result in stable hybrid latexes, from which layered composites are obtained by slow water evaporation. The composite blends present better self-organization of rGO, tendency of segregated network formation, and electrically conductive properties. The in situ composites present decreased aggregation of rGO, uniformly distributed rGO in the polymeric matrix and lower conductivity.