Wettability Control of Copper Surface Using Picosecond Laser for Enhancing Condensation Heat Transfer

Abstract

One of the most important and widely visualized process taking place in nature is condensation. Superhydrophobic surfaces, which facilitates dropwise condensation has been the principal area of research in the last decade or so. Fabrication of superhydrophobic surface can be achieved by either surface modification using mechanical process, surface treatment like coating or by the combination of both. But, the major drawback of coating is its durability and vulnerability. So, in this work we have fabricated a robust surface by means of picosecond laser machining. Apart from being a simple process, this method has an advantage of cutting down the surface fabrication time by several hours as compared to other methods like one-step immersion, electro-deposition, top-down fabrication method, etc. In our work three different work specimens irradiated with different laser power were studied for its surface morphologies by scanning electron microscope (SEM) images and its wettability was measured using contact angle meter. It is found that the wettability of surface changes with different laser power and hence it is possible to control the wettability by adjusting the laser parameters. Condensation experiment was carried out on these different surfaces and its performance was compared with plain surface.