The collapse transition due to water pressure on superhydrophobic surfaces is reversible in the right conditions.
Pontus Forsberg, Fredrik Nikolajeff and Mikael Karlsson from Uppsala University, Sweden, probed the collapse transition on superhydrophobic surfaces completely covered by water, where the air film formed on the surface is closed. The team found that the closed film of trapped air helps stabilise the Cassie state at low pillar densities and that the effect of a small change in pillar sidewall angle can drastically change the collapse behaviour. They also observed the reverse transition, from Wenzel to Cassie state, on densely pillared surfaces at low water pressure.
Read the full article here: Pontus Forsberg, Fredrik Nikolajeff and Mikael Karlsson, Soft Matter, 2010, DOI:10.1039/C0SM00595A
