Hetero-coagulation of polymeric core-corona microspheres

Hetero-coagulation between polystyrene core-poly(vinylamine) (PVAmMS) and p oly(methacrylic acid) corona microspheres in an aqueous phase was studied b y quantitative analysis of precipitated microspheres, absorbance change of mixed dispersions using UV-Vis spectroscopy, transmittance electron microsc opy (TEM) observation, hydrodynamic particle size measurement, and xi-poten tial analysis. It was found that a 12-h incubation was enough for the forma tion of hetero-coagulation. The microspheres were electrostatically aggrega ted to each other. Uniform hetero-coagulated assemblies, which were stably dispersed in an aqueous phase, were obtained with larger size and larger mi xture ratios of microspheres (PMAAMS/PVAmMS). (C) 2000 Elsevier Science B.V . All rights reserved.