A facile method to improve tribological properties of silicon surface by combining nanogrooves patterning and thin film lubrication

Surface micro/nanohierarchical structure designing and thin film lubrication are two main methods to alleviate adhesive and frictional problems encountered by micro/nanoelectromechanical systems (MEMS/NEMS). In this study, silicon surfaces with micro/nano grooves were prepared by photolithography and further chemically modified by multiply-alkylated cyclopentane (MAC) thin films to improve the tribological behaviors of MEMS/NEMS. The effects of nanoscaled roughness (including groove pitch and groove fractional surface coverage) and chemical modification on the wetting and tribological properties of surfaces were systemically investigated. The results of contact angle measurement indicated that the surface hydrophilicity decreases with increasing of surface roughness and lowering of the surface energy (chemical treatment with MACs). Tribological study showed that with the increasing of nanoscale roughness and combined with chemical modification, the tribological properties are greatly improved, which may be affected by real area of contact and the surface chemistry.