Direct observation of the wetting state of Cassie and Wenzel

Abstract

In order to directly observe the solid–liquid-gas three-phase interface, we prepared the superhydrophobic coatings and high adhesion coatings respectively. The surface structure of the two coatings were observed by scanning electron microscopy. The superhydrophobic coating has good micro-nano structure, while the high adhesion coating has only micrometer structure due to the lack of nanometer Polytetrafluoroethylene particles. The wetting state of water droplets on the surface of the two coatings was observed by polarizing microscope and goniometer respectively. The results show that the water droplets in the superhydrophobic coating are in Cassie wetting state, while the water droplets in the high adhesion coating are in Wenzel wetting state. The experimental results provide direct observational evidence for the wetting state of Cassie and Wenzel.