Effect of silk sericin on morphology and structure of calcium carbonate crystal

Abstract

In this paper, silk sericin was employed to regulate the mineralization of calcium carbonate (CaCO₃). CaCO₃ composite particles were prepared by the precipitation reaction of sodium carbonate with calcium chloride solution in the presence of silk sericin. The as-prepared samples were collected at different reaction time to study the crystallization process of CaCO₃ by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and X-ray diffraction (XRD). The results showed that silk sericin significantly affected the morphology and crystallographic polymorph of CaCO₃. With increasing the reaction time, the crystal phase of CaCO₃ transferred from calcite dominated to vaterite dominated mixtures, while the morphology of CaCO₃ changed from disk-like calcite crystal to spherical vaterite crystal. These studies showed the potential of silk sericin used as a template molecule to control the growth of inorganic crystal.

Keywords

silk sericin / calcium carbonate (CaCO₃) / calcite / vaterite / biomineralization