Calcium Carbonate@silica Composite with Superhydrophobic Properties

In this paper, spherical calcium carbonate particles were prepared by using CaCl2 aqueous solution + NH3 center dot H2O + polyoxyethylene octyl phenol ether-10 (OP-10) + n-butyl alcohol + cyclohexane inverse micro emulsion system. Then, nanoscale spherical silica was deposited on the surface of micron calcium carbonate by Stober method to form the composite material. Scanning electron microscope (SEM), X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) were used to characterize the morphology and structure of the composite material. It is found that the surface of the composite material has a micro-nano complex structure similar to the surface of a lotus leaf, making the composite material show hydrophobicity. The contact angle of the cubic calcium carbonate, spherical calcium carbonate and CaCO3@SiO2 composite material were measured. They were 51.6 degrees, 73.5 degrees, and 76.8 degrees, respectively. After modification with stearic acid, the contact angle of cubic and spherical CaCO3 were 127.1 degrees and 136.1 degrees, respectively, while the contact angle of CaCO3@SiO2 composite was 151.3 degrees. These results showed that CaCO3@SiO2 composite had good superhydrophobicity, and the influence of material roughness on its hydrophobicity was investigated using the Cassie model theory.

Automated summary

This paper prepared spherical calcium carbonate particles and deposited nanoscale spherical silica on their surface to form a composite material with a micro-nano complex structure and hydrophobicity. The modified CaCO3@SiO2 composite showed good superhydrophobicity with high contact angle. The influence of material roughness on its hydrophobicity was studied using the Cassie model theory.