Development of MEMS-fabricated Bidirectional ECF (Electro-Conjugate Fluid) micropumps

The previously reported unidirectional ECF micropumps are not applicable to some soft actuators, which need inflating and deflating processes. To overcome this limitation, we propose, design, fabricate and characterize an ECF (Electro-Conjugate Fluid) bidirectional micropump. The simply designed bidirectional ECF micropump has five sets of electrodes. One set of electrodes are composed of two triangular electrodes with a face-to-face distribution and a shared and separated slit electrode. By applying DC voltage to one of the triangular electrodes and grounding the slit electrode, the device can generate an ECF jet along the triangular direction in the microchannel. Therefore, an ECF jet can be achieved in each direction by simply switching the applied DC voltage to one of the two triangular electrodes. This bidirectional ECF micropump without any mechanical moving parts is successfully fabricated by a MEMS-based process. We demonstrate the static and dynamic performance of our bidirectional ECF micropump. In the static evaluation, we primarily focus on the maximum pressure and flow rate generated by the bidirectional ECF micropump. In the dynamic evaluation, we test the responsiveness, model the relationship between switching frequency and output pressure, and compare the theoretical values with the experimental results. Therefore, this study indicates that bidirectional ECF micropumps can be a good candidate for a driving source to realize reciprocating motions.