Lotus Effect coating and its application for microelectromechanical systems stiction prevention

The stiction problem is one of the major factors that limit the widespread use and reliability of microelectromechanical systems (MEMS). The fundamental mechanism to prevent stiction is either increasing the surface roughness, or coating MEMS surfaces with hydrophobic materials. By nature, the Lotus Effect coating is a good combination of rough surface and hydrophobic materials. In this work, the feasibility of using Lotus Effect coatings to prevent MEMS stiction was proposed and investigated. Lotus Effect surfaces were either prepared by creating nanoscale rough structures on a hydrophobic surface with plasma techniques, or by coating functional self-assembled monolayers (SAMs) on nanoporous silica substrates. The effects of surface chemistry and structure on the superhydrophobicity of Lotus Effect materials were studied. The relationship between surface structure, surface wetting, and surface stiction properties of a Lotus Effect surface was also investigated.