A multifunction and bidirectional valve-less rectification micropump based on bifurcation geometry

In this paper, we introduce a novel valve-less rectification micropump based on bifurcation geometry. Three micropumps based on three different bifurcation configurations were designed, fabricated and experimentally investigated. These designs demonstrate the potentials of developing bidirectional micropumps and multifunction microfluidic devices (combined functions of micro pumping and mixing). Polydimethylsiloxane (PDMS) was employed to fabricate the micropumps. Circular piezoelectric transducers (PZT) were used as flow actuators. Detailed fabrication procedures are illustrated. The micropumps were tested against two ranges of actuator frequencies. The first test was conducted in a frequency range between 0 and 100 Hz with small increments of 5 Hz, while the second test was conducted in a frequency range between 0 and 300 Hz with increments of 50 Hz. Ethanol was used as the working fluid in all experiments. A new dimensionless parameter was introduced to evaluate the efficiency of valve-less rectification micropumps and determine the optimum operational frequency. The flow rate and maximum back pressure were measured. Results of experiments confirmed and demonstrated the feasibility of valve-less rectification micropumps based on bifurcation geometry at a low frequency range. Additionally, results showed the potentials of multifunctional, bidirectional, and self-priming micropumps.