Wetting of superhydrophobic surfaces is studied as a multiscale process involving the macroscale (water droplet size), microscale (surface texture size), and nanoscale. It is shown that proper understanding of the contact angle hysteresis and the Cassie-Wenzel transition can be achieved and an apparent contradiction between the kinetic and thermodynamic descriptions can be resolved, if wetting is considered as a multiscale process. Macroscale parameters, such as the contact angle and contact angle hysteresis, cannot be determined from a closed set of macroscale equations, but depend also upon micro- and nanoscale parameters. The validity of the Wenzel and Cassie equations is discussed and generalized Wenzel and Cassie equations are proposed.
contact angle, superhydrophobic surfaces
Superhydrophibicity as a Multiscale Phenomenon, Langmuir
(Accessed October 3, 2023)