Polyoctasilsesquioxane (POSS) has been employed to covalently functionalize nanostructures of TiO(2), ZnO and Fe(2)O(3) as well as carbon nanotubes, nanodiamond and graphene to enable their dispersion in polar solvents. Covalent functionalization of these nanostructures with POSS has been established by electron microscopy. EDAX analysis and infrared spectroscopy. On heating the POSS-functionalized nanostructures, silica-coated nanostructures are obtained. POSS-functionalized nanoparticles of TiO(2), Fe2O3 and graphite were utilized to prepare polymer-nanostructure composites based on PVA and nylon-6,6. (C) 2010 Elsevier Ltd. All rights reserved.