Wetting between Cassie–Baxter and Wenzel regimes: a cellular model approach

Abstract

The cellular model with periodic boundary conditions was proposed for the study of liquid–solid interface properties of solid surfaces decorated by a regular pattern. The solid surface was represented by a mosaic of truncated pyramids of two different slopes of side walls equivalent to a surface covered with triangular grooves of different dihedral angles. On the basis of the computations performed for a single elementary cell, the components of the interfacial energies and the apparent contact angles have been found for different Young contact angles and different tilting angles of the pyramid walls. It was found that at certain sets of angles, the wetting takes place with the partial coverage of the pyramid sidewalls—in between the Cassie–Baxter and Wenzel regimes. The influence of the line tension on the studied surface wettability was also examined. Graphic abstract

Transition from the Wenzel to Cassie–Baxter state by PFOTES/TiO2 nanoparticles leading to a mechanically robust and damage/contamination-recoverable surface

“…25,41 This can be explained by assuming that the addition of 30% PFOTES/TiO 2 NPs was not sufficient to create hydrophobic nano/microstructures on the surface, suggesting that the sample was in the intermediate region between the Wenzel and Cassie-Baxter states. [42][43][44] Thus, it was concluded that 40-60% PFOTES/TiO 2 NPs in the composite were optimal for producing a superhydrophobic surface in the Cassie-Baxter state. The composites containing 40, 50 and 60% PFOTES/TiO 2 NPs with an S a of ∼17 mm were selected as superhydrophobic surfaces.…”

The Effect of Micro/Nano Roughness on Antifouling and Bactericidal Surfaces

“…Then, these three interfacial tensions (solid-liquid, liquid-gas, and solid-gas interfacial tensions) must be balanced to the total surface free energy to describe the corresponding contact angle [39]. However, to explain the behavior of a droplet by the WCA on a rough surface, the protuberances of these surfaces must be considered as the main feature [34,40]. The roughness effect on the surfaces could be described by the fundamental states known as Wenzel State and Cassie-Baxter State to describe how a droplet of water interacts with a surface (Figure 3).…”

Aspects of Wetting of Hydrophobized Surfaces Textured by a Femtosecond Laser

“…The presence of hysteresis between the curve of the textured surface and the straight flat one draws attention. The classic Cassie-Baxter equation can be used to describe its upper part, and the Wenzel equation to describe the lower part [9].…”