Probing non-polarizable liquid/liquid interfaces using scanning ion conductance microscopy

作     者：Yaxiong Gu Ye Chen Yifan Dong Junjie Liu Xianhao Zhang Mingzhi Li Yuanhua Shao Yaxiong Gu;Ye Chen;Yifan Dong;Junjie Liu;Xianhao Zhang;Mingzhi Li;Yuanhua Shao

作者机构：Beijing National Laboratory for Molecular SciencesCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China 

出 版 物：《Science China Chemistry》 (中国科学（化学英文版）)

年 卷 期：2020年第63卷第3期

页      面：411-418页

核心收录：

学科分类：081704[工学-应用化学] 07[理学] 070304[理学-物理化学(含∶化学物理)] 08[工学] 0817[工学-化学工程与技术] 0703[理学-化学] 

基　　金：supported by the National Natural Science Foundation of China(21575006,21335001) the National Key Research and Development Program of China(2016YFA0201300) 

主　　题：micro/nano pipettes scanning ion conductance microscopy microstructure of a non-polarizable liquid/liquid interface 

摘      要：The study of microscopic structure of a liquid/liquid interface is of fundamental importance due to its close relation to the thermodynamics and kinetics of interfacial charge transfer *** this article,the microscopic structure of a non-polarizable water/nitrobenzene(W/NB)interface was evaluated by scanning ion conductance microscope(SICM).Using SICM with a nanometer-sized quartz pipette filled with an electrolyte solution as the probe,the thickness of this type of W/NB interface could be measured at sub-nanometer scale,based on the continuous change of ionic current from one phase to another *** effects for thicknesses of the non-polarizable W/NB interfaces with different electrolyte concentrations,the Galvani potentials at the interface and the applied potentials on the probe were measured and systematically *** experimental setups,that is an organic phase up and an aqueous down,and a reverse version,were employed to acquire the approach *** data were compared with those of an ideal polarizable interface under the similar experimental conditions,and several characteristics of non-polarizable interfaces were *** thickness of a non-polarizable interface increases with the decrease of electrolyte concentration and the increase of applied potential,which is similar to the situation of a polarizable liquid/liquid *** also find that the Galvani potential across a non-polarizable interface can also influence the interfacial thickness,this phenomenon is difficult to observe when using polarizable *** importantly,by the comparison of two kinds of liquid/liquid interfaces,we experimentally proved that much more excess ions are gathered in the space charge layer of non-polarizable interfaces than in that of polarizable *** results are consistent with the predictions of molecular dynamic simulations and X-ray reflectivity measurements.