Fast development of micro/nanoelectromechanical systems (MEMS/NEMS) and high-density storage technology (HDT) have stimulated the development of new materials that require hydrophobic surfaces with low adhesion and friction. Micro/nanohierarchical structures and chemical modification are two useful methods for improving nanotribological properties of mechanical components. In this study, Au surfaces with micro/nanohierarchical structures were prepared by replication of micropatterened silicon surfaces using PDMS and self-assembly of alkanethiol [CH3(CH2)9SH] to create hydrophobic micro/nanohierarchical structures and to improve nanotribological properties of MEMS/NEMS. The effects of nanoscaled roughness (including pillar height and pillar fractional surface coverage) and chemical modification on the wetting and nanotribological properties of surfaces were systemically investigated.
Results show that with the increasing of nanoscale roughness and lowering of surface energy, the surface becomes more hydrophobic, and the adhesive force and friction force are reduced greatly.