Preparation and characterization of novel spica-like hierarchical vaterite calcium carbonate and a hydrophilic poly(vinylidene fluoride)/calcium carbonate composite membrane

Pure vaterite CaCO3 microcrystals with an unusual spica-like hierarchical morphology were synthesized via a simple precipitation method, in which NaHCO3 and ethanol played a key role. The oriented attachment mechanism was responsible for the novel structure. An organic-inorganic composite membrane (PVDF/CaCO3) was prepared and its hydrophilicity was increased dramatically.