A styrene (30% w/w)-butadiene copolymer (3-arm configuration), epoxidized and further functionalized with the -S(O)(2)OH groups was found to be a substrate favoring the deposition of aragonite crystals from stable supersaturated solutions at pH 8.50 and 25degreesC. The crystallization was studied by the constant composition technique, thus making it possible for a relatively large amount of the overgrowths to be formed and to be identified exclusively as aragonite crystals. The apparent order found from kinetic analysis was n = 7.2 +/- 0.8, thus suggesting a polynuclear mechanism. A surface energy of 44 +/- 5 mJ m(-2) was calculated for the growing aragonite phase and a four-ion cluster forming the critical nucleus, according to the classical nucleation theory. (C) 2003 Elsevier Science B.V. All rights reserved.