College of Mechanical Engineering, Donghua University, Shanghai 201620, China.
Nanoscale. 2017 Dec 21;10(1):378-385. doi: 10.1039/c7nr06471c.
Interfacial friction is of crucial importance to ensure the friction-reducing and anti-wear properties of mechanical microstructures in micro/nanoelectromechanical systems (MEMS/NEMS). An ultra-low frictional interface combining hydrophobic 1H,1H,2H,2H-perfluorodecyltrichlorosilane (FDTS) self-assembled monolayers (SAMs) coated on an AFM tip with mechanically exfoliated molybdenum disulfide (MoS) nanosheets deposited on a planar Si/SiO substrate was achieved. The FDTS SAMs/MoS interface between the FDTS SAMs and the MoS nanosheets exhibits an ultra-low friction force that is independent of the relative humidity. The incommensurate contact with ultra-low energy dissipation between FDTS and MoS nanosheets and hydrophobic surface properties lead to this ultra-low frictional FDTS SAMs/MoS interface. Also, the MoS nanosheets have a high elastic modulus, which gives them a smaller contact area than the FDTS SAMs and contributes to the low friction. The excellent hydrophobic properties of both the FDTS SAMs and MoS enable them to be unaffected by the relative humidity by preventing the capillary interaction. This study paves the way for extensive applications in reducing the friction of nanoscale contact interfaces.
界面摩擦力对于确保微/纳机电系统（MEMS/NEMS）中的机械微结构的减摩和耐磨性能至关重要。通过在原子力显微镜（AFM）探针上涂覆疏水性 1H,1H,2H,2H-全氟癸基三氯硅烷（FDTS）自组装单层（SAM），并在平面 Si/SiO 衬底上沉积机械剥离的二硫化钼（MoS）纳米片，实现了具有超低摩擦力的界面。FDTS SAMs 和 MoS 纳米片之间的 FDTS SAMs/MoS 界面表现出超低摩擦力，且与相对湿度无关。FDTS 和 MoS 纳米片之间的非共形接触和超低能量耗散以及疏水性表面特性导致了这种超低摩擦的 FDTS SAMs/MoS 界面。此外，MoS 纳米片具有较高的弹性模量，使其接触面积小于 FDTS SAMs，从而有助于降低摩擦力。FDTS SAMs 和 MoS 都具有优异的疏水性，能够防止毛细相互作用，从而不受相对湿度的影响。本研究为在纳米级接触界面减少摩擦的广泛应用铺平了道路。
