The role of electrochemical reactions during electrophoretic particle deposition
The role of electrochemical reactions during electrophoretic particle deposition
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DOI：
10.1016/j.jcis.2004.05.017
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发表时间：
2004-10-01
影响因子：
9.9
通讯作者：
Cima, MJ
中科院分区：
文献类型：
--
作者：
Kershner, RJ;Bullard, JW;Cima, MJ
采用光刻技术在蓝宝石衬底上制作了铂微电极，用于操纵衬底平面内1.58微米的二氧化硅颗粒。在施加直流电势的过程中，数字视频系统捕捉到了远离电极的粒子的运动以及它们在工作电极上的沉积。通过比较沉积电极和电镀铂修饰电极，研究了电极可逆性的作用。还观察到颗粒在到达电极之前附着在衬底上。测量了颗粒和衬底的Zeta电位。这两个体系不同的表面化学，以及由于阳极产生氢离子而导致的局部pH降低，可以解释粘着现象。使用胶体探针原子力显微镜技术记录了力距离曲线，以直接测量二氧化硅颗粒与蓝宝石衬底的相互作用。这些数据验证了在电极上观察到的粘附性，并为pH的时空降低提供了进一步的支持。还考虑了法拉第过程和电势决定离子在电泳沉积中的扩散作用。(C)2004 Elsevier Inc.保留所有权利。
Platinum microelectrodes were fabricated on a sapphire substrate by lithographic patterning and used to manipulate 1.58 mum silica particles in the plane of the substrate. A digital video system captured the motion of particles far from the electrodes and their deposition onto the working electrode during application of a DC potential. The role of electrode reversibility was investigated by comparing as-deposited electrodes with electrodes modified by electrolytic plating of platinum. Particles were also observed adhering to the substrate before reaching the electrode. The zeta potential of the particles and substrate was measured. The differing surface chemistry of the two systems and a local reduction in pH due to the production of hydrogen ion at the anode can explain the adhesion phenomena. Force distance curves were recorded using a colloid probe atomic force microscopy technique to directly measure the interaction of the silica particles with the sapphire substrate. These data validated the observed adhesion at the electrode and provided further support for the temporal and spatial reduction in pH. The role of Faradaic processes and the diffusion of potential determining ions in electrophoretic deposition were also considered. (C) 2004 Elsevier Inc. All rights reserved.