Scalable and biomimetic anti-oil-fouling photothermal fabric for efficient solar-driven interfacial evaporation

Solar-driven interfacial evaporation (SIE) based on pumping bottom water up to air–water interface for localized heating has raised abundant research interest for clean water production. However, when encountering oil-contaminated water, the oil may block the water transport channels and suppress the water evaporation performance. Here, inspired by the surface structure of mussel, we developed a biomimetic surface coating on a polypyrrole-coated cotton fabric (PGCF) based on the reaction of gallic acid/(3-aminopropyl)triethoxysilane (GA/APTES). GA with the pyrogallol moiety can generate a similar mussel-inspired adhesive coating with the aid of APTES that possesses amino groups mainly through Michael addition/Schiff base reactions. The biomimetic coating with micro- and nano-scale roughness renders the PGCF superhydrophilicity and underwater superoleophobicity, and the obtained flexible fabric showed a stable and efficient water evaporation rate of ∼ 1.54 kg m-2h−1, in pure water and oil-contaminated water including soybean oil, silicone oil, hexadecane, lubricating oil and their mixtures. Moreover, the fabric demonstrates good reusability, and stability against acidic/alkaline/salty environment, providing a simple and easily scalable strategy for the fabrication of flexible SIE fabric for practical use.