A simple route towards graphene oxide frameworks

Lightweight graphene structures have promising applications, for example as separation media, as microreactor environments, for use in energy storage or in microelectronics. The assembly of graphene or its derivatives into such frameworks typically requires rather elaborate and expensive methods which are moreover difficult to scale up. In the present work we propose a simpler route which is based on arresting the temperature induced phase separation in a water-lutidine mixture containing graphene oxide particles. The 2D nature of graphene oxide sheets, combined with an adequate surface chemistry simply controlled by their carbon to oxygen ratio, causes them to collect and assemble at the interfaces and create highly elastic layers which arrest the phase separation process. Soft solid graphene oxide frameworks are created which have sufficient mechanical stability to allow removal of the solvents by freeze drying. The advantage of the method is that the structure and mesh size of the frameworks can be easily controlled, providing direct access to the graphene-oxide surfaces while creating a mechanically robust and percolating network of graphene oxide tiles. This could be used, for example, as electrodes for supercapacitors or fuel cells.