Water-repelling, vapor-resisting, self-cleaning, oil–water-separating, water-purifying, antibacterial Hanji cellulose papers coated with Teflon and ZnO particles via supersonic spraying

Cellulose-based Korean mulberry paper, called Hanji, has been used as a functional material in heaters, supercapacitors, sensors, and light-emitting diodes because of its low weight, high mechanical strength, antibacterial activity, and eco-friendliness. Imparting water resistance property to these functional papers is critical to protect them against potential moisture-associated damage and to ensure their longevity. This study applied supersonic spraying technique to deposit superhydrophobic Teflon and antibacterial ZnO particles on Hanji. The results show that functionalized Hanji deposited with Teflon/ZnO exhibited water-repelling, anti-fogging, and antibacterial properties. Furthermore, the photoinduced water purification and self-cleaning features of functionalized Hanji has been demonstrated. Hanji enabled the passage of purple-colored hexane; however, blue-colored water could not permeate the Hanji filter, demonstrating the oil–water separation capability of Hanji.