High Hysteresis Suspended Wetting State: A Wetting Regime for Controlled Trapping of Drops on Micro‐Trench Covered Surfaces

Wetting of simple liquids on rough surfaces is usually described either by the Cassie–Baxter model where drops are suspended over roughness features with air trapped below, or Wenzel impaled features. According to model, can be surfaces, whereas in easily released upon adding a small tilt. Surfaces very regular surface pattern, such as closely spaced micro-trenches, exhibit so-called High Hysteresis Suspended State (HySS). In this state assume spherical shape below them, characteristic feature state, but show high contact angle hysteresis (up >70°), typical for regime. The HySS regime studied function geometry, applied pressure and mass drop. Through roll-off measurements it shown that controlled trapping conditions generated, captured, however, addition amount energy (e.g., induced tilt) released. parameters used control “depth” trap elucidated.