A latchable paraffin actuated high-pressure microfluidic valve

In this paper, the strongest yet latchable valve in sub-cm³ size for microfluidic applications is presented. The device has an integrated actuator cavity consisting of three segments filled with paraffin and operated by separate heaters. At one of the segments, a membrane valve head is deflected from the expansion of the resistively melted paraffin to close against its valve seat. Different heating sequences provide a latched closed or opened valve. The maximum pressure before any leakage occurred was 1.3 MPa. At higher pressures the leakage increases until the valve is fully open at 2.3 MPa. The valve has an opening and closing time of 9 and 1 s, respectively. At an applied pressure of 0.3 MPa, the closed valve needs to be reactivated every 100 min to remain leakage free, leading to an average power consumption of 4 mW.