Highly transparent, healable, and durable anti-fogging coating by combining hydrophilic pectin and tannic acid with poly(ethylene terephthalate)

The development of environmentally benign, transparent, durable, and healable anti-fogging coating is vital for automobile windshields and food packaging in our daily production and life. The fabrication of existing anti-fogging coatings is often time-consuming in addition to potential toxicity issues. Here, we have reported a highly transparent and healable anti-fogging coating on the surface of poly(ethylene terephthalate) (PET) film by using bioderived pectin and tannic acid (TA) via a facile dip-coating method. The results show that the pectin/TA composite coating endows the PET film with excellent anti-fogging property without sacrificing the transparency of the PET films. This coating can maintain exceptional anti-fogging capabilities in both hot-vapor and cold-warm conditions. In addition, such anti-fogging coatings also exhibit good durability as the anti-fogging capability can be well-retained even after spray rinsing 5 times with high-speed water faucet. Moreover, the scratches or cuts on the coating can be completely healed within 4 minutes of triggering with water. The study provides an innovative methodology for the design of highly transparent, durable, and healable anti-fogging coatings, and offers promising value-added utilization of abundant and renewable biomass.