Superhydrophobic membranes with electrically controllable permeability and their application to “smart” microbatteries

Electrically tunable membranes with controllable permeability have been experimentally demonstrated by combining nanostructured and microstructured superhydrophobic surfaces with the phenomenon of electrowetting. Electrowetting allows dynamical tuning of the contact angle that the liquid forms with the membrane nanofeatures and microfeatures, thus controlling the flow of the liquid through the membrane and, therefore, tuning the permeability of the entire structure. “Smart” electrochemical energy storage cells that can be activated on demand have been built by combining these membranes and microfabricated Zn∕MnO2 electrodes. A typical open-circuit voltage of 1.55V and capacity of 200μAh∕cm2 have been demonstrated.