Abrasion mechanisms of superhydrophobic coating surfaces wetted in Wenzel state

Abstract

Under natural application conditions, water in the forms of condensates and high-speed raindrops tend to form Wenzel contact with the surface of superhydrophobic coatings, and in this case, the effect of the standing water on the abrasion mechanisms of superhydrophobic coatings is not clear. To investigate the issue, comparative tests of abrasion-induced aging on the surface of the superhydrophobic coating under dry, and water infiltration conditions are conducted. A theoretical prediction model of the friction magnitude on the surface of the superhydrophobic coating under the above two conditions is established, and the experimental phenomenon is analyzed based on the theoretical results of the model. The results show that once water wets superhydrophobic surfaces in Wenzel mode, the microscopic rough structures on the surfaces are more likely to fall off under external friction due to the presence of Laplace pressure, which means that the presence of water makes the superhydrophobic surfaces more prone to abrasion-induced aging in this condition.