Permanent adsorption of organic solvents in graphite oxide and its effect on the thermal exfoliation

The dispersion of graphite oxide (GO) in organic solvents followed by their evaporation at relative high temperature resulted in a strong adsorption of the solvent molecules in the graphitic interlayers as confirmed by C-13 magic-angle-spinning NMR. Three series of solvents, alcohols (1-methanol, 1-propanol, 1-pentanol, 1-heptanol), aromatics (benzene, toluene, p-xylene, chlorobenzene) and chloride compounds (dichloromethane, chloroform, carbon tetrachloride) were studied to understand the interaction of graphite oxide with solvents. The distribution of basal interlayer spacing changed due to solvent intercalation and this distribution was particularly different for each solvent series. Even though there was on average 1 solvent molecule per 100 carbon atoms of GO, they had a profound effect on the thermal properties of the resulting GO. The exfoliation temperature was drastically reduced by the presence of the solvents due to the increase of the interlayer spacing and the reducing power of the solvent. (C) 2009 Elsevier Ltd. All rights reserved.