An all-polymer micropump based on the conductive polymer poly(3,4-ethylenedioxythiophene) and a polyurethane channel system

An all-polymer micropump was realized using the conductive polymer poly(3,4-ethylenedioxythiophene) (PEDT) as the active component. The pumping effect originated from an ac potential applied to an asymmetric array of interdigitated electrodes. The PEDT electrodes were fabricated using optical lithography and reactive ion etching, and dimensions down to 2 mu m could be successfully realized. The channel system was made from a flexible thermoplastic polyurethane. The chosen polyurethane exhibited good sealing without the possible contamination issues of silicones, adequate wetting without plasma treatment, and has the potential for mass production, e. g., by injection moulding. The assembled micropump showed a pumping speed of 150 mu m s(-1) at a frequency of 10 kHz and an amplitude of 5 V. Higher potentials resulted in permanent damage to the pump electrodes. Encapsulation of the conducting polymer electrodes by an insulating polymer layer prevented electrode break-down at the cost of pumping efficiency. Continuous pumping for 40 min at 20 mu m s(-1) without detectable pump degradation was demonstrated in this configuration.