We present an electrostatically operated normally opened microvalve for gas flow control. The valve is made of thermoplastic materials and uses a new fabrication method. The voltage required to close the 0.9 mm wide microvalve was ∼350 V for fluid (air) pressure ∼1kPa.
A new technique  has been developed to fabricate valves, micromixer [2, 3] and other microfluidic structures, by patterned welding of compliant thermoplastic films using Universal Laser System CO2 laser. The normally opened valve is electrostatically actuated by applying the voltage on its metalized thermoplastic surfaces. There is no movable membrane or cantilever which closes the fluid path as reported in many other electrostatic microvalves. The walls of the channel collapse toward each other when sufficient voltage is applied, thus effectively closing the fluid path. The material used is 1.4 μm thick Mylar™ sheets (DuPont) coated on one side with ∼10nm of gold.