Formation of colloid crystals from polymer-modified monodisperse colloidalsilica in organic solvents

The formation of colloid crystals from monodisperse and polymer-modified si lica particles in organic solvents was investigated. Maleic anhydride-styre ne copolymer-modified silica formed crystals in polar organic solvents, whi ch dissolve the copolymer, while the original colloidal silica formed cryst als in organic solvents which were miscible with water. The critical volume fraction in the crystal formation of the polymer-modified silica was lower than that from the unmodified silica in the same solvent. Polystyrene- and poly(methyl methacrylate)-modified silica particles also crystallized in o rganic solvents, but the features of the formation were different from thos e of poly(maleic anhydride-styrene)modified particles.