Uematsu Yuki, Iwai Suguru, Konishi Mariko, Inagi Shinsuke
Department of Physics and Information Technology, Kyushu Institute of Technolohy, Iizuka 820-8502, Japan.
PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan.
Langmuir. 2024 Sep 16;40(38):20294-301. doi: 10.1021/acs.langmuir.4c02798.
Solid surfaces in contact with nonaqueous solvents play a key role in electrochemistry, analytical chemistry, and industrial chemistry. In this work, the zeta potentials of cotton membranes in acetonitrile solutions were determined by streaming potential and bulk conductivity measurements. By applying the Gouy-Chapman theory and the Langmuir adsorption isotherm of ions to the experimental data, the mechanism of the electrification at the cotton/acetonitrile interface is revealed for the first time to be solely due to ion adsorption on the surface, rather than proton dissociation at the interface. Different salts were found to produce opposite signs of the zeta potentials. This behavior can be attributed to ion solvation effects and the strong ordering of acetonitrile molecules at the interface. Furthermore, a trend of the electroviscous effect was observed, in agreement with the standard electrokinetic theory. These findings demonstrate that electrokinetics in acetonitrile, a polar aprotic solvent, can be treated in the same manner as in water.
与非水溶剂接触的固体表面在电化学、分析化学和工业化学中起着关键作用。在这项工作中，通过流动电位和体电导率测量确定了棉膜在乙腈溶液中的zeta电位。通过将 Gouy-Chapman 理论和离子的 Langmuir 吸附等温线应用于实验数据，首次揭示了棉/乙腈界面处的起电机制完全是由于离子在表面的吸附，而不是界面处的质子解离。发现不同的盐会产生相反符号的zeta电位。这种行为可归因于离子溶剂化效应和乙腈分子在界面处的强有序排列。此外，观察到了电黏效应的趋势，这与标准电动理论一致。这些发现表明，在极性非质子溶剂乙腈中的电动现象可以与在水中以相同的方式处理。
