COATING OF UNIFORM INORGANIC PARTICLES WITH POLYMERS .2. POLYANILINE ON COPPER-OXIDE

Uniform spherical colloidal copper oxide particles were coated with po lyaniline in the reaction mixtures containing CuO, aniline, water, eth anol, and polyvinyl alcohol (PVA) without the use of a soluble oxidant . The final dispersion consisted of a mixture of CuO with a polymer sh ell and independent polyaniline (latex) particles. The reaction betwee n aniline and CuO follows the well-known mechanism by which the metal oxide undergoes reductive dissolution while the organic monomer is oxi dized. Oxygen and PVA are essential to the polymerization of aniline i n the system. Oxygen may function as an oxidant to promote the polymer ization, while PVA forms micelles that enhance the reaction rate throu gh emulsion polymerization and protect polyaniline from hydrolysis. A temperature higher than 90 degrees C is necessary for the reaction to achieve a coating of more than 10% by weight in 48 h. The thickness of the polymer shell can be adjusted by changing the reaction time and t he concentrations of aniline, copper oxide, and ethanol. The structure of the produced polymer corresponds to that of polyleucoemeraldine. ( C) 1995 Academic Press, Inc.