Autonomous colloidal crystallization in a galvanic microreactor
Abstract
We report on a technique that utilizes an array of galvanic microreactors to guide the assembly of two-dimensional colloidal crystals with spatial and orientational order. Our system is comprised of an array of copper and gold electrodes in a coplanar arrangement, immersed in a dilute hydrochloric acid solution in which colloidal micro-spheres of polystyrene and silica are suspended. Under optimized conditions, two-dimensional colloidal crystals form at the anodic copper with patterns and crystal orientation governed by the electrode geometry. After the aggregation process, the colloidal particles are cemented to the substrate by co-deposition of reaction products. As we vary the electrode geometry, the dissolution rate of the copper electrodes is altered. This way, we control the colloidal motion as well as the degree of reaction product formation. We show that particle motion is governed by a combination of electrokinetic effects acting directly on the colloidal particles and bulk electrolyte flow generated at the copper-gold interface.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Oct 01, 2012
- Source ID
- 10.1063/1.4755807
Entities
People
- Christian Punckt
- Dudley A. Saville
- Ilhan A. Aksay
- Linda Jan
- Peng Jiang
- Thomas A. Frewen
- YannÃs G. Kevrekidis
Organizations
- Defense Advanced Research Projects Agency
- Princeton University