Hydration of Graphite Oxide in Electrolyte and Non-Electrolyte Solutions

Pressure induced insertion of liquid media was studied for graphite oxide (GO) immersed in excess amounts of aqueous copper acetate and sucrose solutions and compared to previous experiments with GO immersed in solute-free water media. Compression of GO in copper acetate solution resulted in significant enhancement of high pressure anomaly compared to pure water: interlayer distance reached 17.4 angstrom at 2.3 GPa while for pure water the maximal observed layer separation was 13.08 angstrom. Compression of GO in sucrose solution was found to be very similar to compression in solute-free water. These results confirm that copper ions can be pressure-inserted into GO structure while the expansion of structure is attributed to osmotic swelling. Sucrose dissolves in water in molecular form (nonelectrolyte) which results in weaker absorption into the GO structure and the absence of osmotic swelling. Pressure induced insertion of various solutions into the GO structure could possibly be promising for synthesis of new graphite intercalation materials or graphene-related composites.