Instant grafting polymerization of styrene initiated by microwave radiation on the surface of graphite nanosheets (GNs) was carried out. The stability of the modified GN dispersions in different solvents indicated significant changes in the surface properties of GNs. In comparison with GNs without modification, the modified GNs showed more stable suspensions in a nonpolar organic solvent such as toluene and were more likely to form a precipitate when dispersed in distilled water, a polar solvent. Fourier transform infrared and thermogravimetric analysis were used to confirm the functionalized GNs. (C) 2008 Wiley Periodicals, Inc.