Microfabrication of dual-opposite electrodes inside a microchannel by means of multiphase laminar flow with density difference

An alignment-free and low-cost microfabrication technique for dual-opposite silver electrodes inside a polydimethylsiloxane (PDMS) microchannel is presented using multiphase fluids with density difference in a laminar flow regime without a photolithographic process. The electrode patterns were created using chemical deposition at the interface between a silver electroless plating solution (denser fluid) and a reducer solution (less dense fluid). The gravitational force induced by the density difference causes a slight rotation of the interface in the downstream direction, thereby resulting in the dual-opposite electrodes having individual electrical connection patterned on the top and bottom walls of the PDMS microchannel.