Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA.
Langmuir. 2013 Feb 26;29(8):2498-505. doi: 10.1021/la303757a. Epub 2013 Feb 11.
The mechanisms leading to the deposition of colloidal particles in a copper-gold galvanic microreactor are investigated. Using in situ current density measurements and particle velocimetry, we establish correlations between the spatial arrangement and the geometry of the electrodes, current density distribution, and particle aggregation behavior. Ionic transport phenomena are responsible for the occurrence of strongly localized high current density at the edges and corners of the copper electrodes at large electrode separation, leading to a preferential aggregation of colloidal particles at the electrode edges. Preferential aggregation appears to be the result of a combination of electrophoretic effects and changes in bulk electrolyte flow patterns. We demonstrate that electrolyte flow is most likely driven by electrochemical potential gradients of reaction products formed during the inhomogeneous copper dissolution.
研究了导致胶体颗粒在铜金电镀微反应器中沉积的机制。通过原位电流密度测量和颗粒速度测量，我们建立了电极的空间排列和几何形状、电流密度分布以及颗粒聚集行为之间的相关性。离子传输现象导致在大电极分离时铜电极的边缘和角落处出现强烈局部化的高电流密度，从而导致胶体颗粒优先聚集在电极边缘。优先聚集似乎是电泳效应和电解质整体流动模式变化的综合作用的结果。我们证明了电解质流动很可能是由不均匀铜溶解过程中形成的反应产物的电化学势梯度驱动的。
