Facile Fabrication of Honeycomb-Patterned Thin Films of Amorphous Calcium Carbonate and Mosaic Calcite

Facile fabrication of honeycomb-patterned thin films of amorphous calcium carbonate (ACC) and mosaic calcite was achieved via colloidal lithography at the solution surface. At first, honeycomb-patterned ACC (HP-ACC) thin films were fabricated by a polymer-induced ACC coating of the monolayer colloidal crystal (MCC) template at the air/water interface. Subsequent controlled crystallization of the preformed HP-ACC thin films under different conditions led to honeycomb-patterned, crystalline films with different microstructures. In particular, honeycomb-patterned, mosaic calcite thin films composed of single-crystalline calcite plates could form when thermal treatment at 400 °C was applied to the amorphous films. Additionally, dye molecules were incoporated into the HP-ACC thin film during its formation, enabling further functionality of the patterned thin film with fluorescence. Furthermore, the highly ordered HP-ACC thin films possessed brilliant structural colors and exhibited typical photonic properties.