Three-dimensional relief structures of CaCO₃ crystal assemblies formed by spontaneous two-step crystal growth on a polymer thin film

Three-dimensional relief structures of CaCO₃ are formed by spontaneous two-step crystal growth on a polymer matrix in the presence of an acidic polymer. The first step is self-organization of thin-film crystals with flat surface displaying periodically changing crystallographic orientations. In the second step, the relief structures consisting of needlelike crystals are spontaneously assembled on the thin-film crystals obtained in the first step. This approach may have great potentials to control the complex structures of inorganic/polymer composite materials.