A disposable, dead volume-free and leak-free in-plane PDMS microvalve

The align-less three-dimensional in-plane PDMS microvalve is presented. The device is entirely made from PDMS. The hemisphere with smooth surface ensures dead volume- and leak-free, which is formed by bulging of UV-curable glue. Also, the spin-coated PDMS membrane is bonded to the molded PDMS substrate for 3D structure fabrication indicating that align-less assembly is possible. In particular, the curing ratio, defined as the ratio of soft cure time and the full cure time of PDMS at the soft cure temperature, is for the first time introduced for PDMS-to-PDMS bonding. The best bonding judged from bonding feature and bonding strength is shown at the temperature of 50degreesC and 29 min implying the curing ratio of 0.06. Finally, a membrane-inserted in-plane PDMS microvalve is fabricated and its performance is visually evaluated. (C) 2004 Elsevier B.V. All. rights reserved.