Scanning glass microelectrode technique for investigating temperature-dependent electrical properties

Abstract

Recent progresses in ionic current analyses related to micro- and nano-object sensing, electrochemical sensors, and liquid pollution monitoring have attracted significant attention. Micro- and nanoscale sensors with high spatial resolution and high signal-to-noise ratios are also effective for obtaining detailed understanding of ion transport phenomena. We have developed a glass microelectrode technique for measuring the electrical potential distribution by scanning through liquids. It enables us to directly evaluate electrical properties with a spatial resolution equal to the glass tip diameter, which is less than 1 μm. Herein, we optimize the channel and cell structures for the analysis of temperature-dependent properties, which allows us to measure the temperature dependence of conductivity and viscosity in the range of 303--333 K based on the Stokes--Einstein relation. The proposed method, which directly measures the spatial distribution of electrical potential, is suitable for analyzing conductivity, viscosity, and concentration without preprocessing calibration.