Superhydrophobic coatings with robustness and multifunctionality for wood protection by rod-like ZnO/lignin nanosphere composites design

The development of superhydrophobic coatings for wood protection using biomass materials signifies a trend in future advancements. However, ensuring the durability of biomass-based superhydrophobic coatings under harsh conditions remains a formidable challenge. Here, rod-like ZnO/lignin nanosphere (LNS) composites are obtained using co-assembly, followed by changing the addition time of LNSs to control their sizes. The composites demonstrate good performance in visible-light photocatalysis test, about 47 % of the degradation of methylene blue solution within 150 min. A robust and multifunctional superhydropphobic coating is further fabricated by as-prepared ZnO/LNS composites on wood surface, with a contact angle of 163.7 ± 0.5° and a sliding angle of 2.1 ± 0.2°. Owing to the reinforcing effect imparted by rod-like ZnO, the coating demonstrated resistance to 20 cycles of abrasion and withstood 240 cycles of tape peeling. The coating also shows robustness against other mechanical and chemical damages. Furthermore, through the synergistic effect of ZnO and LNSs, the coated wood demonstrates outstanding visible light-driven photocatalytic activity and flame retardation for practical application. This study aims to facilitate the improvement and development of inorganic/lignin composites, thereby offering a novel pathway for the fabrication of modified wood products with high-performance.