A disposable, dead volume-free and leak-free monolithic PDMS microvalve

A new fabrication method of a membrane-inserted pneumatically-driven microvalve is presented. The device is entirely made from PDMS. To ensure dead volume-free and leak-free, the valve chamber is formed with smooth surface using molding of UV-curable bond. Also, to place a PDMS membrane on the molded PDMS substrate, bonding with spin-coated PDMS membrane is performed, indicating to align-less assembly. As a reference of bonding characterization, the curing ratio, defined as the ratio of soft bake time and hard cure time of PDMS at the same soft cure temperature, is introduced. The best bonding feature is obtained at the curing ratio of 0.06. The maximum tensile bonding strength is examined. Finally, the performance of the membrane-inserted monolithic PDMS valve is tested.