Formation of graphene oxide films at the liquid/liquid interface

Abstract

A strategy of employing graphene oxide (GO) nanosheets to prepare large-area GO films is proposed in this work. The films are prepared by injecting GO suspension in a mixture of water and ethanol (H2O + EtOH) at the liquid/liquid (hexane/water, C6H14/H2O) interface and forming the GO films at the interface. After evaporation of C6H14, GO films at the air/(H2O + EtOH) interface are transferred onto solid substrates by the horizontal lifting deposition, and large area (2.5 cm × 2.5 cm) of homogeneous GO films with the thickness of 5.4 nm and the roughness of 3.6 nm is obtained. The formation scheme of the GO films at the C6H14/(H2O + EtOH) interface is discussed considering the density difference between the C6H14, (H2O + EtOH), and H2O, as well as the interaction between the GO nanosheets. This facile strategy paves a new path for preparation of large ultrathin GO films from GO nanosheets, which is of great importance for the preparation of GO-based materials to be used in supercapacitor electrodes, transparent conductive films and field-effect transistors.