Valving in microchannels via electrodeposition on solid electrolytes

Microfluidic technology is currently being applied to analytical systems but suitable valving elements are proving to be difficult to implement. We have recently developed a novel way to electrically regulate flow through microchannels via a structure that can be made using readily available microfabrication techniques. An electrical signal is used to stimulate silver deposition on a thin Ag-Ge-Se solid electrolyte layer in a small region of a channel. The electrodeposited silver, which is a high surface area fractal structure less than 1 μm in height and several hundred μm long, changes the fluid-surface interaction. In this paper we demonstrate that this effect can be used to regulate pressure-driven flow in a microchannel.