Aminoazobenzene@Ag modified meshes with large extent photo-response: towards reversible oil/water removal from oil/water mixtures

Photo-responsive materials with superwetting properties, especially in the azo-based class, have been used in water treatment because of their smart performance on wettability changes. However, their transformation extent in wettability has always troubled researchers. Here, we modified nano-Ag pine needles and aminoazobenzene (AABN) on polydopamine (PDA) pre-treated porous meshes, realizing a large-extent reversible photo-responsive wettability transformation from highly hydrophobic to highly hydrophilic. The contact angle is about 150.0° after being exposed to visible light, and is about 10.0° under 365 nm UV light. Accordingly, the modified mesh can achieve photo-responsive removal between oil and water from oil/water mixtures. This facile and universal approach based on trans–cis isomerization of AABN could be endowed to various commercial conductive meshes. Moreover, the modified meshes exhibit satisfactory removal efficiency, reusability and physical/chemical stability, which are more promising for practical applications such as fuel recycling, remote controlled oil/water separation and astronautical resource regeneration.