A photochemical-processed simultaneously oleophobic/hydrophilic polymer coating
Yongjin Wang and Lei Li
Department of Chemical and Petroleum Engineering, University of Pittsburgh, 3700 O’Hara Street, Pittsburgh, PA 15261
Simultaneously oleophobic/hydrophilic coatingss have many important applications, including anti-fogging, detergent-free cleaning and oil-water separating. However, this type of coating was rarely reported and all the existing ones are difficult to synthesize and expensive, which makes the real-life application not feasible. In the current study, we have investigated the photochemical approach to achieve simultaneous hydrophilicity/oleophobicity for cost-effective commercially available perfluorinated polymers. The contact angle testing showed that UV irradiation of nanometer-thick perfluorinated polymers on a silica substrate has resulted in the simultaneous oleophobicity/hydrophilicity. The ellipsometry and X-ray photoelectron spectroscopy (XPS) results suggested that UV irradiation causes the covalent bonding between the polymer backbone and the silica substrate, which promotes the formation of the polymer network and thus render the surface simultaneously hydrophilic/oleophobic. The potential of such coatings for application in anti-fogging, detergent-free cleaning and oil-water separation has been demonstrated.