Simple structured polydimethylsiloxane microvalve actuated by external air pressure

Abstract This article describes a simple structured microvalve made of polydimethylsiloxane (PDMS) and glass. For easy operation, the microvalve is actuated by external air pressure. The microvalve is fabricated by replica moulding using a negative photoresist (SU-8) as the mould. For low cost and biocompatibility, PDMS is used as the chip material. The PDMS valve is bonded to a Pyrex glass substrate using an O2 plasma surface treatment. It was found that no leakage occurs under a valve-actuating air pressure of 0.35 MPa when the injection pressure of liquid in the microchannel of the valve is 0.01-0.04 MPa. The fabricated microvalve is applied to a microfluidic chip having one inlet and two outlet channels. Fluid flow is controlled by the microvalve.