Microstructured SiO2 surface repellant to liquids without coating

摘要

We report the first superhydrophobic surface made of a material that is highly wetting (Young's angle below 10 degrees) to the liquid in service. The concept is proposed and experimentally confirmed by microstructuring silicon dioxide (SiO2), which is highly wetting to aqueous liquids (e.g. water). In pushing the surface geometry to a doubly re-entrant topology, the key is in the geometric details of the microstructures and how to fabricate them. Tested on micrograting surfaces, the measured apparent contact angle agreed with the theory, and the pressure the microstructures can resist against wetting transition was found consistent with the claimed design.