Formation of various polymorphs of calcium carbonate on porous membrane by electrochemical approach

Calcium carbonate (CaCO3) formation was observed without surface modification of the organic template and in the absence of chemical additives such as macromolecules and divalent cations. Our innovative electrochemical approach that involves the use of an alternating current facilitated the crystallization of CaCO3 polymorphs on a porous polymer membrane. A solution of calcium chloride (CaCl2) and sodium carbonate (Na2CO3) was filled in a glass cell, and the porous membrane was interposed in the cell. A sine waveform of 10 Hz was applied to the platinum electrodes using a high-speed bipolar power supply. An alternating current was generated for 60 min. The crystal morphology and crystal structure of the resulting hybrid membrane were studied. In this electrochemical approach, versatile polymorphs of vaterite, aragonite, and calcite were formed on the membrane, thereby showing that the alternating current induced the formation of various polymorphs of CaCO3 on the porous membrane even in the absence of any additives.