Facile fabrication of durable mesh with reversible photo-responsive wettability for smart oil/water separation

Oil/water separation is becoming a global obstacle since the oil-water mixture is hard to on-demand separate the desired component (water or oil) in practical application. To overcome this dilemma, herein, we report a spray-coating method to fabricate flexible surfaces reversible switch between hydrophobic and hydrophilic states with UV/vis illumination. Decorated with novel tetrapod-ZnO (T-ZnO), polydimethylsiloxane (PDMS) hydrophobic coating and 4-Aminoazobenzene (AAB) moieties, the modified nylon (Polyamide, PA) mesh possesses a porcupinefish-like structure surface with reversible photo-responsive wettability and multimechanical damage-resistant ability. The dominant advantage from reversible photo-responsive wettability composite lies in that they can take advantage of the AAB photoisomerization, the wettability of this smart material surface dynamically converted between hydrophilic and hydrophobic character in nature with UV and vis light irradiation. In consequence the intelligent material can be transformed reversibly between “oil-removing” and “water-removing” state by alternate lighting mode. More importantly, owing to the porcupinefish-like surface of the modified PA, the photo-responsive material showed prominent anti-multimechanical deformation and damages ability, which could withstand repeated mechanical deformation as well as multiple practical applications.