Investigating the use of nanoscale bilayers assembly on stainless steel plate for surface hydrophobic modification and condensation

摘要

This study investigated the use of nanoscale bilayers assembly for hydrophobic surface modification on stainless steel plate and its effect on condensation. This study first performed nanoscale bilayers assembly method, with the addition of a fluorosilane treatment using chemical vapor deposition (CVD), to modify the surface structure and thereby the wettability of the surface at 15, 20, and 30 bilayers. Experimental results showed 15 bilayers to be the optimal number of bilayers among the samples tested, resulting in the largest contact angle of 150° (compared to 70° on unmodified surface), corresponding to the highest surface hydrophilicity; however, beyond 15 bilayers there seems to be no significant changes or improvements to hydrophobicity. Visualization of the condensation process also indicated later formation of film condensation on super-hydrophobic (15 bilayers) surface, and by tilting the condensation surfaces at 90°, the self-cleaning property of the super-hydrophobic surface allows water droplets to roll off the surface due to gravity before formation of film condensation, while large water droplets still remain stuck on unmodified surface. Therefore, by allowing the condensation process on the super-hydrophobic surface to continuously cycle back to droplet condensation, there is great potential for condensation enhancement on super-hydrophobically modified surface.