Photocatalytically Active Superhydrophilic/Superoleophobic Coating
Jingwei Lu, Xiaotao Zhu, Xiao Miao, Yuanming Song, Li Liu, Guina Ren, Xiangming Li
Abstract
Hydrophilic materials are easily fouled by organic contaminants owing to their high surface energy, and this oil-fouling problem severely hinders their use in practical applications. To address this challenge, herein, a hydrophilic coating with oil repellency and photocatalytic activity is developed by a spray-casting process. In the air surrounding, a water droplet spreads over the coating surface completely, while oil droplets exhibit contact angles more than 150° and moving on the coating freely. The water-wetted coating still had oil repellency, as the water layer on the coating surface can act as a lubricant to repel oil. Although methylene blue aqueous solution contaminates the coating by wetting it completely, these water-soluble organic molecules can be removed by UV illumination, due to the photocatalytic activity of the coating. Exploiting its water-attracting and oil-repelling properties, the coating deposited on a copper mesh is applied as a multiplatform for oil-water separation with high separation efficiency. This study provides a novel and efficient way to solve the oil-fouling problem of hydrophilic materials.