Versatile and environmentally benign polyurethane coatings enabled by the multiple facets of tannic acid

Developing environmentally friendly coatings that are substrate-independent, extremely transparent, and omni-liquid-repellent remains a daunting task. Herein, we present a highly versatile polyurethane coating (TA-g-PDMS) that incorporates plant-derived tannic acid (TA) and polydimethylsiloxane (PDMS). The highly cross-linked network suppresses macroscopic phase separation and endows the resulting TA-g-PDMS coating with up to 99 % transparency. The PDMS smooth layer formed on the outermost surface repels both water and oil, and has anti-smudge and self-cleaning properties. Even after 500 repetitive writing and erasing cycles, the coating still maintains its excellent anti-graffiti properties. Due to the superior adhesion of TA, this coating can approach top 5B adhesion and can be applied to a variety of substrates. By utilizing the antioxidant properties of TA, silver nanoparticles can be generated in the coating by in situ reduction, resulting in an excellent antibacterial rate of more than 99 %. Furthermore, the self-cleaning properties of the coating coupled with the UV shielding ability imparted by TA enhance the photostability and durability of organic solar cells (OSCs). We present an eco-friendly method of fabricating versatile and durable coatings for a wide array of uses.