Self-Assembly and Tribological Properties of Carbon Nanotubes Film on Silicon Substrates

Carbon nanotubes (CNTs) film was prepared on silicon (Si) substrate with a 3-aminopropyl-triethoxysilane (APTES) film as the interlayer in a multistep self-assembly process. The formation and microstructure of the CNTs film were characterized by using scanning electron microscopy (SEM), water contact angles (WCAs) and X-ray photoelectron spectrometry (XPS). Tribological properties were evaluated with a UMT-2MT reciprocating friction tester. Results show that the CNTs were successfully assembled on Si substrates by chemical bonding between functional groups. CNTs film exhibited excellent friction reduction, high load-bearing capacity and antiwear ability. The friction coefficient was reduced drastically from 0.7 to 0.16, with markedly prolonged antiwear lifetime compared to bare Si substrates or APTES film. These superior tribological properties are attributable to the remarkable mechanical properties of CNTs and strong bond properties with the APTES film. CNTs film is thus expected to find wider application as high-performance lubricating film in micro/nanoelectromechanical systems (M/NEMS) in future.