Preparation of lignin nanospheres based superhydrophobic surfaces with good robustness and long UV resistance

Lignin is an ideal substance for preparation of functional materials. Specifically, lignin nanospheres (LNPs) are formed by self-assembly of lignin molecules and show great application prospects in drug delivery, electrochemistry, catalysis, etc. At present, most superhydrophobic surfaces are mainly built using non-degradable inorganic particles and are still beset by defects such as poor environmental performance, easy aging, and low mechanical strength. In this study, an aqueous mixture containing LNPs, cellulose nanocrystals (CNCs) and polyvinyl alcohol (PVA) was sprayed onto wood surfaces and then modified by 1H,1H,2H,2H-perfluorooctyltrichlorosilane (FOTS) to obtain a superhydrophobic surface. In the superhydrophobic surface, LNPs were used as the main structural materials instead of inorganic particles, CNC was used as a reinforcement material and PVA was used as an adhesive. The resulting superhydrophobic surface showed a water contact angle (WCA) of 162°, good robustness resistance and long UV resistance in which the superhydrophobicity was still retained after exposure to ultra-high UV light (power of 1000 W) for 7 h, providing more directions for high-value application of lignin.