Characterization of the wettability of thin nanostructured films in the presence of evaporation.
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 ( approximately 10microm) porous films.
Rogacs
Anita
A
Department of Mechanical Engineering, Stanford University, 440 Escondido Mall, Bldg 530, Room 224, Stanford, CA 94305, USA. rogacs@stanford.edu
Steinbrenner
Julie E
JE
Rowlette
Jeremy A
JA
Weisse
Jeffrey M
JM
Zheng
Xiaolin L
XL
Goodson
Kenneth E
KE