Organo- and Water-Dispersible Graphene Oxide-Polymer Nanosheets for Organic Electronic Memory and Gold Nanocomposites

A solution-processable graphene oxide (GO)-polymer complex, consisting of GO nanosheets with covalently grafted poly(tert-butyl acrylate) (PtBA) brushes, was prepared via surface-initiated atom transfer radical polymerization (ATRP). The grafted hydrophobic polymer brushes substantially enhance the solubility of GO in organic solvents, and the GO-g-PtBA nanosheets can form a uniform and stable dispersion in toluene. The functionalized GO nanosheets can also be integrated into an electroactive polymer matrix. Bistable electrical conductivity switching behavior and a nonvolatile electronic memory effect were demonstrated in a composite thin film of poly(3-hexylthiophene) (P3HT) containing 5 wt % GO-g-PtBA in an Al/GO-g-PtBA+P3HT/ITO sandwich structure (ITO = indium-tin oxide). Hydrolysis of GO-g-PtBA produces water-dispersible GO-g-PAAc (PAAc = poly(acrylic acid)) nanosheets and allows the preparation of gold nanoparticle-decorated GO-g-PAAc nanofilms from aqueous dispersions.