Wettability and evaporation enhancement for heat transport devices by high performance oxide layer

Wettability and evaporation control is a key issue to enhance heat transport performance for heat transport devices such as heat pipes and vapor chambers. In this study, in order to enhance heat transport performance of copper-based heat transport devices, utilization of a high performance copper oxide layer is proposed. This layer has high wettability, which leads to strong evaporation performance. The copper oxide layer is generated by adjusting its oxidation temperature and time. In order to evaluate the wettability and evaporation characteristics, contact angle and droplet behavior on a high temperature surface are evaluated with a high speed video camera. It is confirmed that the contact angle strongly depends on the oxidation temperature and time, and in most cases hydrophilic state where the contact angle is less than 10 degrees is confirmed. In addition, a wetting limit temperature of a droplet drastically increases and also the life time shortens compared with that of a bare surface. These results suggest that precisely controlled copper oxide layer can enhance the heat transport performance of heat pipes and vapor chambers.