Rogacs, A., Steinbrenner, J.E., Rowlette, J.A., Weisse J.M., Zheng, X.L.L., Goodson, K.E., 2010, “Characterization of the Wettability of Thin Nanostructured Films in the Presence of Evaporation,” Journal of Colloid and Interface Science, Vol. 349, pp. 354-360.
Vapor chambers using conventional porous membrane wicks offer limited heat transfer rates for a given thickness. This limitation can be addressed through wick nanostructuring, which promises high capillary pressures and precise control of the local porosity. This work develops a measurement technique for the wettability of nanostructured wicks based on optical imaging. Feasibility is demonstrated on a hydrophilic silicon nanowire array (SiNW) synthesized using the Vapor–Liquid–Solid (VLS) growth mechanism followed by surface plasma treatment. The wettability is determined by comparing the time-dependent liquid interface rise with a model that accounts for capillary, viscous, and gravitational forces and for evaporation. This model is demonstrated to be useful in extracting internal contact angle from thin porous films.