Evaporation of water droplets from hydrophobic and hydrophilic nanoporous microcantilevers

Abstract

The evaporation dynamics of water droplets from the surfaces of well-defined nanoporous substrates, anodic aluminum oxide (AAO) cantilevers with various pore sizes, were investigated. The AAO cantilever surfaces were modified to be either hydrophilic or hydrophobic. After placing a water droplet on the cantilevers, variations in the resonance frequency and deflection during evaporation were related to the changes in mass and stress of the cantilever, respectively. The dynamics of water droplet evaporation on a hydrophilic AAO cantilever was found to be significantly different from that measured on a hydrophobic AAO cantilever due to the permeation of water into the hydrophilic nanopores. (c) 2011 American Institute of Physics. [doi: 10.1063/1.3541958]