Abstract
The purpose of this study is to investigate the distribution of the electrostatic potential at a liquid-liquid interface. The interfacial potential was measured by the nanoscale laser-induced fluorescence (LIF) using two fluorescent dyes whose concentrations change depending on the interfacial potential and the evanescent wave employed as an excitation light source. Two buffer solutions with different hydroxide ion concentrations were mixed in a T-shaped channel and the mixed solution formed an oil-water interface at the downstream. The significant change in the fluorescent intensity ratio due to the introduction of two buffer solutions was visualized as a distribution. The result showed that the electrostatic potential was varied spatially by the hydroxide ion concentration.
