Redispersible Reduced Graphene Oxide Prepared in a Gradient Solvent System

Abstract

We designed a gradient solvent strategy for the reduction of graphene oxide, matching the hydrophilic properties of graphene oxide (GO) and reduced graphene oxide (RGO), respectively. A third solvent was added dropwise to regulate the hydrophilic variation of the continuous gradient system which maintained the whole reduction process without aggregation, and the obtained RGO dispersions could maintain stability for a long time. The separated RGO solid powder can be directly ultrasonically redispersed in N-methyl-pyrrolidone (NMP) with an average particle size as low as 200 nm. Furthermore, RGO with a high C/O ratio of 13.75 was prepared on the basis of the gradient solvent system. Using different structures of dispersants and polymers as representatives, we employed successive solvent rinsing, thermal solvent extraction, and thermal treatment to study adsorption and desorption. It was found that the above measures differed significantly in the removal of surface sorbates. The selected fatty alcohol polyoxyethylene ether (AEO) series achieved a good balance between the system dispersion and surface adsorbate removal. The conductivity was originally 5236 S m−1, and it increased from 9024 to 18,000 S m−1 after thermal treatment at 300 and 500 °C, respectively.

The Janus Structure of Graphene Oxide and Its Large-Size Conductive Film Strip Pattern

“…Based on what has been reported in the literature, as well as our previous work [ 59 , 60 ], this has been shown to be a regular laminated stacked structure. In general, if the two sides of GO are uniformly oxidised, this will destroy the symmetry of the ring structure and it becomes difficult to have a layered structure, so we presume that GO is an asymmetric oxidised structure.…”