A polymeric paraffin micropump with active valves for high-pressure microfluidics

We present the potentially strongest micropump in sub-cm³ size yet for microfluidics, using simple processes and materials such as epoxy, paraffin, and polyimide. Utilizing the large volume expansion associated with the melting of paraffin for actuation, a pump consisting of two active valves and one pumping chamber operated by three identical paraffin actuators has been realized. UV-curable epoxy, which encloses the paraffin, forms the channel structure and joins the glass cover, actuator membrane and resistive heaters for melting the paraffin, is the main construction material. With water as a pumping fluid and a 2 V drive voltage, the valves were subjected to pressures up to about 1 MPa without showing any leakage. A flow rate of 74 nl/min was obtained in normal operation.