Non-Negligible Diffusio-Osmosis Inside an Ion Concentration Polarization Layer

作     者：Inhee Cho Wonseok Kim Junsuk Kim Ho-Young Kim Hyomin Lee Sung Jae Kim 

作者机构：Department of Electrical and Computer Engineering Seoul National University Seoul 08826 South Korea Department of Mechanical and Aerospace Engineering Seoul National University Seoul 08826 South Korea Institute of Advanced Machines and Design Seoul National University Seoul 08826 South Korea Big Data Institute Seoul National University Seoul 08826 South Korea Interuniversity Semiconductor Research Center Seoul National University Seoul 08826 South Korea 

出 版 物：《Physical Review Letters》 (Phys Rev Lett)

年 卷 期：2016年第116卷第25期

页      面：254501-254501页

核心收录：

学科分类：07[理学] 0702[理学-物理学] 

基　　金：National Research Foundation of Korea [CISS-2011-0031870, 2012-0009563, 2014-048162, 2016R1A1A1A05005032] Korean Health Technology RND project [HI13C1468, HI14C0559] BK21+ program of Creative Research Engineer Development IT, Seoul National University 

主　　题：Diffusion Electrochemistry Osmosis Ionic fluids Micromechanical devices 

摘      要：The first experimental and theoretical evidence was provided for the non-negligible role of a diffusio-osmosis in the ion concentration polarization (ICP) layer, which had been reported to be in a high Peclet number regime. Under the assumption that the hydrated shells of cations were stripped out with the amplified electric field inside the ICP layer, its concentration profile possessed a steep concentration gradient at the stripped location. Since the concentration gradient drove a strong diffusio-osmosis, the combination of electro-osmotic and diffusio-osmotic slip velocity had a form of an anomalous nonmonotonic function with both a single- and multiple-cationic solution. A direct measurement of electrolytic concentrations around the layer quantitatively validated our new investigations. This non-negligible diffusio-osmotic contribution in a micro- and nanofluidic platform or porous medium would be essential for clarifying the fundamental insight of nanoscale electrokinetics as well as guiding the engineering of ICP-based electrochemical systems.