Translucent Lignin-Based Omniphobic Polyurethane Coating with Antismudge and UV-Blocking Dual Functionalities

Polyurethane materials are made from polyisocyanates and polyols, most of which are synthesized from nonrenewable fossil chemicals. Herein, we use biomass lignin as a renewable polyol to prepare translucent and omniphobic polyurethane coatings through covalent immobilization of a small amount of polydimethylsiloxane (PDMS) as a dewetting agent. It was found that such PDMS-containing lignin-based polyurethane (lig-PU-PDMS) coatings were able to repel various contaminating liquids, which could easily slide off from the coating surfaces without leaving any traces. Complex liquids such as ink and paint were difficult to adhere to the coating surface and could be easily removed with paper, towels, or rags. Such coatings were applicable for various substrates including steel and plank. Moreover, these coatings provided good UV-blocking properties. Thus, the design of this study has a guiding significance for the application of lignin in water-proofing, antismudge, and UV-blocking multiple-functional coatings and extends the high-value utilization field of lignin biomass.