A fast membrane actuator in the current stabilization regime

Abstract

Microfluidic systems such as labs-on-a-chip or drug delivery devices require a built-in actuator to drive pumps and valves. The electrochemical actuator is a promising option due to its compact size, low power consumption and high integration capability, but long time of gas termination makes this device rather slow. Recently, the actuator of a new type was demonstrated, which is based on the electrolysis of water performed by microsecond voltage pulses of alternating polarity (AP). It operates several orders of magnitude faster than the conventional DC actuator, but extreme operation conditions lead to the electrode degradation and rapid decrease of the performance. In this work, we demonstrate the long-term operation of the actuator without significant loss of the stroke. This result is achieved due to a new working regime, in which the time interval between series of AP pulses is filled with single polarity (SP) pulses, in contrast with the normal regime, where the SP pulses are not used. The new regime is realized by a specially developed pulse generator that tracks the current flowing through the electrodes and adjusts the amplitude of SP pulses to stabilize the current at a given level. We verify the current stabilization regime at the actuator with the oxidized Ti electrodes and compare it to the normal operation.