Hydrophilic coating of copper particle monolayer wicks for enhanced passive water transport

Abstract

Passive water transport through thin-surface wicks made of heat conducting material is important for developing thermal management devices such as heat pipes and spreaders. In this study, we demonstrated the hydrophilic coating of a Cu particle monolayer wick for enhanced water transport. We fabricated a Cu particle monolayer using Cu powder with a nominal particle diameter of 100 μm and determined the particle size distribution using scanning electron microscopy (SEM). We observed a remarkable change in the water contact angle on the application of a hydrophilic coating, which demonstrated the enhanced passive water transport. The elemental mapping of Cu, O, and Si obtained by electron probe microanalysis confirmed the deposition of the SiO2-based coating material on each Cu particle. Although the Cu particles were only partially covered by SiO2, a remarkable enhancement in wettability was achieved. Finally, we conducted a rate-of-rise experiment to quantitatively characterize the water transport performance of the coated Cu particle monolayer. Thus, we propose hydrophilic coating as a simple and effective method to enhance passive water transport through Cu particle monolayer wicks.