Constructing Scalable Membrane with Tunable Wettability by Electrolysis‐Induced Interface pH for Oil–Water Separation

Abstract The tunable wettability by pH‐stimulus has great potential in liquid adhesion, transport, collection, and separation due to its rapid response and wide control range. However, achieving pH‐regulated wettability on the selected region of material without acid–base contamination presents a distinct challenge for the existing methods. Here, a scalable conductive network membrane is prepared with switchable wettability by regulating interfacial pH. The generation and diffusion of interfacial pH on the selected region of the membrane are regulated through the confinement electrolysis process, which is adapted to both spatial arrangements of the conductive network and the electrical potential. By regulating the interfacial pH (>13), the wettability of the selected region can change from superhydrophobicity (Water contact angle = 150°) to superhydrophilicity/underwater superoleophobicity (Water contact angle = 0°) without additional reagent in 30 s under 15 V. Based on the switchable wettability and precise controllability, the prepared membrane can efficiently realize on‐demand oil–water separation (>99%) and in situ extraction‐back extraction. The membrane with switchable wettability is programable and free of acid–base contamination, which may have broad practical application potential in intelligent fluid‐related systems.