Graphene nanosheets deposited on polyurethane films by self-assembly for preparing transparent, conductive films

This study prepared graphene nanosheet (GNS)-based transparent, conductive films (TCFs) by a self-assembly method. We used the water-borne polyurethane (WPU, with sulfonate functional groups) film as the substrate. Aggregation and restacking of the GNS were inhibited efficiently by attracting the octadecyl trimethyl ammonium chloride surfactant (cationic surfactant) to the surface of the GNS (GNS-O), which can in turn attract sulfonate groups to the WPU surface. The GNS-O was deposited on WPU to form TCFs. We obtained highly transparent and electrically conductive thin films after treatment with nitric acid (GNS-OA). The GNS-OA composite films showed a maximum sheet electrical resistance of 1.5 x 10(3) Omega square(-1), with a light transmittance of up to 79% and a ratio of DC conductivity to optical conductivity of 0.88.