Sphincter-like micro actuators based on electroactive polymer

We present sphincter-like micro actuators enabling the reversible adjustment of the aperture area of one or several orifices using the swelling of the conjugated electroactive polymer (EAP) polypyrrole. One possible application is the controlled diffusion-or infusion-based transport of drugs out of miniaturized delivery devices. Three different orifice configurations are proposed and swelling could be doubled by avoiding closed EAP-structures. The actuators do not contain any complex moveable part and can be controlled using low voltages (1 V) and currents (peak down to 45 muA).