Accelerating the movement of microfluids in microchannels

The motion of fluid in the system can be controlled by some particular methods. Although the science of microfluidics has increased to a high extent, most methods still suffer from flow-rate control problems. Passive pumping is a way making inlet droplets flow towards the outlet. In this paper a technique will be reported in which passive pumping is used in a micromixer device. According to this method, since the radius is inversely related to the pressure (Young– Laplace equation), the smaller drop moves towards the larger drop. Therefore, the bigger droplet is placed at the output directing smaller droplets at the inlets of the micromixer. By making the outlet hydrophilic, theradius of poured droplet on the reservoir port tends to infinity. On account of the fact that pressure is inversely proportional to the radius, the maximum pressure will be achieved. Consequently, a more efficient way of passive pumping can be obviously utilized which can be helpful in various applications such as point of care tests (POCT) in which the process will be both facilitated and accelerated thanks to on-site diagnosis. As a result, hydrophilic surfaces can be extremely promising for microfluidics transportation. Herein, we present a straight forward method for this issue in which plasma torch is applied to the output in a way that other parts of the polydimethylsiloxane (PDMS) should be covered causing the hydrophobic inlet droplets to move faster.

Keywords:

microfluidics , passive pumping , point of care tests