Calcium Carbonate@silica Composite with Superhydrophobic Properties.

Yitong Ma,Pei Tian,Nong Wang,Malayphone Bounmyxay,Yiwen Zeng

doi:10.3390/molecules26237180

Yitong Ma, Pei Tian + Show 3 more

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https://doi.org/10.3390/molecules26237180

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Abstract

In this paper, spherical calcium carbonate particles were prepared by using CaCl2 aqueous solution + NH3·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 Stöber 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°, 73.5°, and 76.8°, respectively. After modification with stearic acid, the contact angle of cubic and spherical CaCO3 were 127.1° and 136.1°, respectively, while the contact angle of CaCO3@SiO2 composite was 151.3°. 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.

Highlights

Over thousands of years of natural selection, living organisms, including all plants and animals on our earth, have become evolutionarily optimized functional systems
CaCO3 @SiO2 composite materials were formed by loading nanosized silica onto spherical calcium carbonate
A new composite material of CaCO3 @SiO2 was prepared by combining the nano structure with the micron structure, and the superhydrophobicity of the material was realized by increasing the surface roughness

Summary

Introduction

Over thousands of years of natural selection, living organisms, including all plants and animals on our earth, have become evolutionarily optimized functional systems. One of their most fascinating properties is their ability of self-cleaning, which means that their surfaces can repel contaminants such as solid particles, organic liquids, and biological contaminants by the action of rolling-off water drops. The contact and sliding angle of a drop are a quantitative measure of self-cleaning behavior. It is considered that both hydrophobicity and low contact angle hysteresis are necessary for self-cleaning surfaces [12,13,14]. The contact angle hysteresis is related to the roughness and surface tension of the material. In order to make a superhydrophobic surface (water contact angle > 150◦ ), the nanometer scale roughness and hydrophobic surface (smooth surface contact angle > 90◦ ) are two basic requirements [15]

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