Polymer microvalve based on anisotropic expansion of polypyrrole

An actuator fabricated from the conductive polymer polypyrrole using microfabrication techniques is presented. This actuator utilizes the anisotropic volume change, which occurs under application of an electric field in polypyrrole grown in the presence of NaDBS. This volume change is in direction normal to the substrate, and is several times larger than lateral volume change utilized in polypyrrole microactuators to date. The actuator is applied in a microfluidic valve where membrane and microchannels are fabricated from a transparent elastomer using soft lithography. The use of elastomer enabled a good valve seal and encapsulation of the electrolyte used for polypyrrole actuation.