Construction of lignin/CaCO3/CS superhydrophobic coating with excellent heat resistance, abrasion resistance, UV resistance and oil-water separation

Superhydrophobic coatings are developed rapidly due to the eye-catching versatility, but still suffer from problems of insufficient environmental protection, poor heat resistance, and weak UV resistance. Here, a stable and versatile lignin/calcium carbonate (CaCO3)/chitosan (CS) superhydrophobic coating on the wood (beech) could be successfully prepared by simple one-step spay. In the coating system, enzymolysis lignin was employed as the main materials to construct surface rough structure, which was enhanced with both CaCO3 and CS, methyltrimethoxysilane (MTMS) and hexadecyltrimethoxysilane (HDTMS) as the hydrophobic modifiers and polydimethylsiloxane (PDMS) as the adhesive. The resulted coating shows good superhydrophobicity (water contact angle of 161.1° and sliding angle of 8°), as well as excellent heat resistance (superhydrophobicity still maintaining under 200 °C), UV resistance (10 h of high-intensity UV irradiation). In addition, when PU sponge was used as the substrate, the stable oil-water separation could be achieved. In view of the good performance and simple preparation, the superhydrophobic coating displays a good application prospect.