Synthesis of calcium carbonate particles with carboxylic-terminated hyperbranched poly(amidoamine) and their surface modification

Abstract

Size-controlled CaCO₃ particles were obtained using a carbonate-controlled addition method with a carboxylate-terminated hyperbranched poly(amidoamine) (HYPAM-ONa). The crystalline phase of CaCO₃ particles was determined to be thermodynamically unstable vaterite. The average size of the CaCO₃ particles decreased from 1.3±0.2 to 0.36±0.18 μm with an increase in the incubation time of HYPAM-ONa-Ca²⁺ solution from 3 min to 72 h. Interactions of the CaCO₃ particles in aqueous dispersions with different types of commercially available ionic polymers that is, poly(acrylic acid), poly(sodium 4-styrenesulfonate), poly(diallyldimethylammonium chloride) and poly(arylamine) (PAAM) were studied. Surface coating of the CaCO₃ particles with PAAM, an aqueous dispersion, was successfully achieved by the addition of a specified concentration of the polymer. The surface-coated CaCO₃ particles with gold nanoparticles were obtained by addition of an aqueous solution of gold nanoparticles stabilized with HYPAM-ONa to an aqueous dispersion of the CaCO₃ particles and subsequent addition of HAuCl₄ and formaldehyde as a reducing agent.