Deposition of calcium carbonate disks on polyelectrolyte multilayer matrices by the alternate soaking process

CaCO3 was deposited on layer-by-layer-assembled polyelectrolyte multilayer films composed of poly(acrylic acid) and poly(vinylamine hydrochloride) by the alternate soaking of the films in aqueous solutions containing Ca2+ and CO32− ions. Upon the first soaking process, 42% of the assembled polymers were desorbed, and the amounts of CaCO3 deposited increased with more soaking. Scanning electron microscopic and atomic force microscopic observations revealed the growth of disk-shaped CaCO3 with smooth upper surfaces. X-ray diffraction patterns showed the typical but broad peaks for aragonite, one of three crystals for CaCO3. These observations suggested that a mixture of amorphous and aragonite CaCO3 was prepared on the present multilayer matrices. Parameters, which determine the amounts of deposited CaCO3, are discussed herein. It was found for the first time that the alternate soaking of layer-by-layer assembled multilayer films potentially fabricated CaCO3 disks with tunable sizes and density on the film surface.