Pneumatically driven peristaltic micropumps utilizing serpentine-shape channels

This study presents a novel pneumatic micropump featuring a serpentine-shape (S-shape) microchannel. Fluid is driven through the device by the hydrodynamic pressure generated by the peristaltic action of membranes located at the intersections of the fluidic microchannel and the S-shape microchannel. The pneumatic micropump is fabricated in PDMS (polydimethylsiloxane) using MEMS (micro-electro-mechanical-systems)-based techniques. The micropump provides an improved pumping rate and is controlled using a single electromagnetic valve (EMV) switch. The experimental results reveal that the pumping rate can be increased by increasing the operational frequency of the EMV, the pressure of the externally supplied compressed air or the number of membranes. As the compressed air travels along the S-shape microchannel, it causes the membranes to deflect. The time-phased deflection of successive membranes along the microchannel length generates a peristaltic effect which drives the fluid along the microfluidic channel. The maximum attainable pumping rate is influenced by the time interval between the deflections of adjacent membranes, and is therefore affected by the geometric characteristics of the serpentine microchannel. The back pressure of the serpentine-shape micropump is measured at a fixed peak frequency to prove its ability to overcome the fluidic resistance. The optimum operating conditions and geometric parameters of the micropump are verified experimentally. It is found that the maximum pumping rate is 7.43 µl min −1 and is provided by a micropump with seven membranes actuated by 20 psi air pressure and 9 Hz operational frequency.