Single bubble dynamics on a superhydrophilic surface with artificial nucleation sites

Abstract

The dynamics of single bubbles on a superhydrophilic surface with well-defined nucleation sites are studied. The superhydrophilic surfaces are prepared by forming CuO nanostructures on a silicon substrate with an isolated microcavity. The bubble departure diameter in water is observed to be 2.5 times smaller and the growth period 4 times shorter on the superhydrophilic surface than on a silicon substrate. A model balancing the buoyancy with the surface tension force captures the departure diameter well, confirming the importance of wettability on bubble dynamics. The present work helps develop new surfaces for controlled phase change heat transfer and bubble-based micro-devices. (C) 2010 Elsevier Ltd. All rights reserved.