title: Polarity-dependent electrochemically controlled transport of water through carbon nanotube membranes.
abstract: We demonstrate here that water can be efficiently wet and pumped through superhydrophobic aligned multiwalled nanotube membranes by application of a small positive dc bias. At a critical bias ( approximately 1.7 V), with the membrane acting as anode, there is an abrupt transition from a superhydrophobic to hydrophilic state. Interestingly, this phenomenon is strongly polarity dependent; for a negative bias applied to the membrane, 2 orders of magnitude higher bias is required for the transition. The polarity and voltage-dependent wetting that we report could be used to controllably wick fluids through nanotube membranes and could find various applications.
authors.affiliation: Department of Mechanical, Aerospace and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, USA.
authors.forename: Zuankai
authors.initials: Z
authors.lastname: Wang
authors.forename: Lijie
authors.initials: L
authors.lastname: Ci
authors.forename: Li
authors.initials: L
authors.lastname: Chen
authors.forename: Saroj
authors.initials: S
authors.lastname: Nayak
authors.forename: Pulickel M
authors.initials: PM
authors.lastname: Ajayan
authors.forename: Nikhil
authors.initials: N
authors.lastname: Koratkar