Preparation of Composite Materials by Using Graphene Oxide as a Surfactant in Ab Initio Emulsion Polymerization Systems

In this letter, we report a simple and unexpected method of producing polymer-graphene oxide (GO) composite materials via ab initio emulsion polymerization in water. On the basis of the recent reports concerning the surfactant-like behavior of GO for stabilizing oil-in-water emulsions, we prepared exfoliated GO sheets with lateral dimension approximately 200 nm for use as surfactant in the emulsion polymerization of styrene. We observed an expected classic surfactant behavior to produce stable nanoparticles at extremely low GO loadings (<0.1% w/w); however, at higher concentrations a highly aggregated, fibrous morphology was formed. This morphology is predominantly due to the electrolyte concentration (ionic strength) of the aqueous phase resulting in heterocoagulation of growing oligomers with dispersed GO sheets, which offers a convenient route toward preparing hybrid materials.