Direct sensing of temperature dependence of electric field and conductivity of liquids using glass microelectrodes

In recent years, ionic current analyses for liquid environments have attracted significant attention. Ionic responses obtained from confined small spaces provide information and new findings from the viewpoint of micro- and nano-scales. Signals in such small spaces are weak and often disturbed by noise, and thus, the measurement technique in liquids has been an important issue. Herein, we have developed a novel technique to directly measure the electric field in a small test section, which enables us to determine the electrical conductivity and concentration. Upon scanning a glass microelectrode, the spatial distribution of the electric field is visualized. In this study, the temperature dependence of electrical conductivity is analyzed by scanning the electric field in the temperature range from 303 to 333 K, using LiCl, NaCl, and KCl solutions. The relationship between the electric field, conductivity, and viscosity of liquids is discussed. In summary, the glass microelectrode technique has been shown to enable quantitative analysis of the physical properties of liquids from spatially localized temperature-dependent quantities.