[1Ba01-10] 摩擦の科学研究部会「SDGsの実現に向けた摩擦観測と制御」

[1Ba06] Water adsorption on hydrophilic surfaces: Chemical homogeneity “before” friction

*Shu-hei Urashima^1,2, Taku Uchida¹, Yoshikazu Homma², Hiroharu Yui^1,2 (1. Department of Chemistry, Faculty of Science, Tokyo University of Science, 2. Water Frontier Research Center in TUS)

Frictional force on material surfaces in atmosphere varies with relative humidity. Although this humidity dependence is generally rationalized by the condensation of adsorbed water to the contact area, molecularscopic description of the condensation is unclear. Furthermore, it is still under debate whether the adsorbed water before applying the frictional force forms uniform film on the material surfaces or not. For describing the relationship between the water condensation and the frictional force under atmospheric conditions, it is important to clarify at first the condensation structure of the adsorbed water before applying frictional force at molecular scale. In the present study, we analyzed the structural changes of adsorbed water with varying the relative humidity on silica, which is one of the typical hydrophilic materials, by surface-selective vibrational spectroscopy.