Fabrication and characterization of superhydrophobic surface by using water vapor impingement method

In this research, superhydrophobic coating with average static contact angle of 166° has been successfully prepared by using a new surface roughening method. Discussion on the applicability of Cassie and Wenzel equations used to determine surface parameters from experimental data is being included as well. This new surface roughening method uses accelerated water vapor to impinge wet film forming crater-like structure surface; analogous to meteor striking earth forming crater. Wet film is comprised of aluminium tri-sec butoxide, propan-2-ol, and ethyl acetoacetate according to molar ratio of 1:10:1. Craters with diameter distribution of 1–20 μm were formed on the roughened surface. It was then subjected to 10 min of immersion in boiling water, 20 min of immersion in fluoroalkylsilane solution, and 10 min of 100 °C hot air treatment producing superhydrophobic coating. This superhydrophobic crater-like structure surface has approximately 8% solid-to-liquid area fraction and high roughness value of 6.4. These values were obtained from both Cassie and Wenzel equations but with some minor modification in order to fit them into experimental data. Average sliding angle of 2.6° and hysteresis value of 10° were recorded.