Reversible Thermochromic Superhydrophobic BiVO4 Hybrid Pigments Coatings with Self-Cleaning Performance and Environmental Stability Based on Kaolinite

The inferior acid resistance and high cost of BiVO₄ pigments seriously hinder their wide applications in some fields. Inspired by the superhydrophobic properties of some plants and insects in nature, the reversible thermochromic superhydrophobic coatings with self-cleaning performance and environmental stability were successfully designed by combining with the surface roughness of kaolinite/BiVO₄ hybrid pigments (Kaol/BiVO₄-HP) and the modification with hexadecyltrimethoxysilane (HDTMS). When the concentration of HDTMS was 4.58 mmol/L, the yellow superhydrophobic coatings exhibited excellent self-cleaning properties and chemical and environmental stability. Furthermore, the superhydrophobic Kaol/BiVO₄-HP coatings exhibited the reversible thermochromic behavior with the change of the external temperatures from room temperature to 270 °C. Interestingly, this facile strategy also can be used to fabricate a series of superhydrophobic clay mineral/BiVO₄-HP coatings based on the different clay minerals, and there was no relationship between the superhydrophobic properties of the coatings and the morphologies of clay minerals, which was different from the reported color superhydrophobic coatings prepared with Maya-like blue pigments. Thus, the low-cost and thermochromic superhydrophobic clay mineral/BiVO₄-HP coatings presented a promising application in temperature sensors and switches with the excellent weather resistance to record and monitor the temperature changes.