Normally-open Monolithic PDMS Membrane Microvalve with Isotropically-etched Valve Seat for Robust Microfluidics

Journal: Journal of Micromechanics and Microengineering (J MICROMECH MICROENG)

Abstract: We present a monolithic polydimethylsiloxane (PDMS) membrane microvalve with an isotropically-etched valve seat for robust microfluidic applications. In order to avoid bonding or sticking of PDMS membrane to valve seat during bonding process, the valve seat was wet-etched to be separated from PDMS mating surface by ca. 5 ？m. The simple wet etching technique allows for fabrication of an anti-bonding architecture in a scalable manner and therefore intrinsically prevents conformal contact between PDMS membrane and valve seat when no external force is applied (i.e., normally-open). This approach enables the permanent device assembly so that microfluidic chip can be operable in a wide range of fluid pressure (e.g., over 200 kPa) without any leakage and sticking problems.