An Empirical Study on Dropwise Condensation Occurred on Surfaces Hydrophobized Using a Single-Step Electrodeposition

Condensation occurs on surfaces in two different forms, including fines and dropwise condensation. Investigations have shown that in especial conditions, dropwise condensation could have better heat transfer than filmwise condensation. Dropwise condensation occurs on hydrophobic and superhydrophobic surfaces. The rate of heat transfer depends mostly on the preparing process of hydrophobic surface. Two main features of hydrophobic surfaces are existing micro-nanostructures and their low surface energy. In this paper, a one-step electrodeposition process is used to produce the necessary micro-nano structures on copper surfaces for the first time. A self-assembled mono-layer of 1-Octaecanethiol as surface energy reducing agent. The resulting hydrophobic surfaces are used in dropwise condensation experiments. Effects of different parameters of the electrochemical cell such as electrical current and time of process on the dropwise condensation heat transfer are investigated. The heat transfer experiments are performed on a device fabricated for this purpose. The surface of the specimens are analyzed using Scanning Electron Microscopy images and X-ray diffraction analysis. The results show that some microstructures made from copper grow on the surface. The results show that the current and process time have positive effects on the dropwise condensation heat transfer. It has been seen that surfaces fabricated in low electrodeposition time (15 and 45 sec) have a worse dropwise heat transfer rate than filmwise condensation heat transfer. On the other hand, higher electrodeposition times (135 sec) give 2-4 times higher heat transfer than filmwise heat transfer in subcooling range lower than 10 Kelvin.