Electrolysis-assisted recovery of superhydrophilicity from superhydrophobized surfaces

Abstract

Superhydrophilicity has been widely used in industrial applications. Superhydrophilic metal surfaces are subject to becoming superhydrophobic when exposed in air, which is due to the accumulation of airborne organics on the surfaces. This wettability transition disables the desired functions and causes dramatic inconvenience in industrial applications. Therefore, a nondestructive treatment method is needed to recover the original superhydrophilicity. Herein, an electrolysis-assisted method is proposed to realize the recovery of wettability in which the metal surfaces are used as cathode in the electrolysis processing system. Bubbles resulted from electrolysis can effectively and efficiently remove the airborne organics absorbed on the surfaces, resulting in the recovery of superhydrophilicity. In addition, it is experimentally verified that this method can also be used to get rid of the low energy substances such as fluoroalkylsilaneis, from the chemically-treated superhydrophobic surfaces. What's more, the hierarchical microstructures and substrates are free of damage. The method can be repeatedly employed for the recovery of superhydrphilicity whenever the superhydrophilic surfaces are superhydrophobized. Notably, as far as we have investigated, this approach can be applied to metal materials such as Al, Ni, W, Ti, Cu and stainless steel.