title: Directed motion of colloidal particles in a galvanic microreactor.
abstract: 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.
authors: Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA.
authors: Linda
authors: L
authors: Jan
authors: Christian
authors: C
authors: Punckt
authors: Boris
authors: B
authors: Khusid
authors: Ilhan A
authors: IA
authors: Aksay
mesh_terms: D003102:Colloids / Q000737:chemistry; D003300:Copper / Q000737:chemistry*; D055664:Electrochemical Techniques; D004566:Electrodes; D004573:Electrolytes / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D010316:Particle Size; D013499:Surface Properties
chemical_list: D003102:Colloids; D004573:Electrolytes; D006046:Gold; D003300:Copper