The kinetics of vaterite crystallization on styrene (30% w/w)-butadiene copolymer (branched) containing -C(O)CH3 functional groups was investigated by the constant composition method. The polymer along with the functional groups stabilizes this calcium carbonate polymorph which transforms slowly to calcite. The apparent order for the crystallization process was found to be 1.3 +/- 0.1 indicative of a surface diffusion control mechanism. The number of ions forming the critical nucleus was found to be n* = 3. The surface energy of the growing phase was 45 mJ m(-2). The formation of vaterite initiated through the interaction of Ca2+ ions of the supersaturated solution with the negative end of the -C = O bond. (C) 2003 Elsevier B.V. All rights reserved.