Measurements for load capacitance of fluid film lubrication with diffused electric double layer

除低速外，流体动力润滑具有减小摩擦的作用。由于分子吸引力（即范德尔华力）在微纳系统中起主导作用，流体动力负载电容不足以避免低速条件下表面之间的直接接触。“Stiction”就是一个例子。开发新型液体润滑机制对MEMS具有重要意义。首席研究员提出了一种利用电双层的新机制。数值模拟结果表明，在表面间隙10 ~ 100纳米处，排斥力起作用。本研究采用扫描探针显微镜（SPM）测量负载电容，考察探针半径、外加电压、离子种类和浓度、表面间距等因素对负载电容的影响，并考虑双电层纳米润滑的能力。对SPM进行了改进，用于测量液体中的法向力和摩擦力。在探针顶端粘贴球形环氧树脂，并溅射沉积10nm的金膜。离子液体是未来润滑的候选材料。研究了在10 ~ 150mv电压下测得的斥力特性。

Hydrodynamic lubrication has the effect of reducing friction except at a low speed. Since molecular attractive force (i.e. van del Waals force) has been predominant effect in micro-nanoscopic system, hydrodynamic load capacitance has not been enough to avoid direct contact between surfaces in low velocity condition. "Stiction" is an example. It is important that development of new lubrication mechanism for MEMS in liquid. Head investigator proposed a new mechanism using electric double layer. It was simulated numerically as result that repulsive force has been taken effect at 10 to 100 nanometers gap between surfaces.In this study, load capacitance has been measured by SPM (Scanning Probe Microscope), for influences of probe radius, applied voltage, kind and concentrations of ion and distance between surfaces for consideration of ability of nano-lubrication by electrical double layer.SPM has been modified for measurements of normal and frictional force in liquid. A spherical epoxy resin has been pasted at the top of probe tip with sputter-deposited 10nm Au film. Ionic liquid, which is candidate for future lubrication, has been used. Characteristics of repulsive force measured at 10 to 150 mv voltage have been investigated.