CNRS-Université de Lorraine, Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), UMR 7360 CNRS, 15 avenue du Charmois, F-54500 Vandœuvre-lès-Nancy, France.
Physical Chemistry and Soft Matter, Wageningen University & Research, Stippeneng 4, 6708, WE, Wageningen, The Netherlands.
Adv Colloid Interface Sci. 2020 Jan;275:102074. doi: 10.1016/j.cis.2019.102074. Epub 2019 Nov 19.
This article is concerned with the nature and impact of bipolar faradaic electron transfer processes in the context of measuring electrokinetic parameters at the interface between an electronically conductive substrate such as a solid metal layer, and a liquid medium. More specifically, it analyses the steady state electric current through the electrodic substrate layer in terms of its short-circuiting effect on the system's electrokinetic quantities, such as the streaming potential. Ample attention is paid to the electrodic behaviour of the chosen metal and its electron transfer characteristics with respect to redox functions in the medium. The electrochemical reversibility of redox couple species is expressed in terms of their oxidation and reduction rate constants as compared to their diffusive transport rates under lateral flow conditions. High values for rate constants lead to high reversibilities and large bipolar leaking currents through the metal substrate. In turn, high electron transfer rate constants generate large reductions in measured values for electrokinetic quantities such as streaming potentials that further become a non-linear function of the pressure gradient applied through the fluidic chamber. The present article presents an overview of theoretical and experimental approaches of this intricate coupling between bipolar electrode kinetics and electrokinetics and the impact from Hans Lyklema's contributions. It highlights not only the implications of bipolar faradaic depolarisation processes in electrokinetics but also the importance of bipolar electrochemistry principles in various electroanalytical applications reported for e.g. the control of microfluidic flows, for surfaces functionalisation, particles manipulation or for the wireless detection of electroactive analytes.
本文关注的是在测量电子导电基底（如固体金属层）与液体介质之间界面处电动参数时，双极性法拉第电子转移过程的性质和影响。更具体地说，它根据系统电动量（如流动电势）的短路效应来分析通过电极基底层的稳态电流。本文充分关注所选金属的电极行为及其电子转移特性，以及介质中氧化还原功能。氧化还原对物质的电化学可逆性用其氧化和还原速率常数相对于其在横向流动条件下的扩散传输速率来表示。高的速率常数导致高的可逆性和通过金属基底的大双极性漏电流。反过来，高的电子转移速率常数会导致流动电势等电动量的测量值大幅降低，而流动电势进一步成为通过流体腔施加的压力梯度的非线性函数。本文概述了这种双极电极动力学与电动学之间复杂耦合的理论和实验方法，以及 Hans Lyklema 的贡献的影响。它不仅强调了双极性法拉第去极化过程在电动学中的影响，还强调了双极电化学原理在各种电分析应用中的重要性，例如微流控流的控制、表面功能化、粒子操纵或对电活性分析物的无线检测。
