Non-wetting and phase transitions induced by spatial and temporal patterns
Small-amplitude fast vibrations and small surface micropatterns affect properties of various systems involving wetting, such as superhydrophobic surfaces and membranes. The mathematical method of averaging the effect of small fast vibrations is known as the method of separation of motions. The vibrations are substituted by effective force or energy terms, leading to vibration-induced phase control. The best known example of that is the stabilizationb of an inverted pendulum on a vibrating foundation (the Kapitza pendulum); however, the method can be applied to a number of various situations including wetting. A similar averaging method can be applied to surface micropatterns leading to surface texture-induced phase control. We argue that the method provides a framework that allows studying such effects typical to biomimetic surfaces, such as superhydrophobicity, membrane penetration and others. Patterns and vibration can effectively jam holes and pores in vessels with liquid, separate multi-phase flow, change membrane properties, result in propulsion, and lead to many other multiscale, non-linear effects. These effects can be used to develop novel materials.