Microfluidic Reactor for Polymer Synthesis ! Polymer Synthesis within Microfluidic Reactor Microfluidic Rotary Pump

Conventional mechanical pumps based on centrifugal or axial turbomachinery are not suitable for micro and nano scales where the Reynolds numbers are usually small. Centrifugal and inertial forces are negligible, and viscous forces dominate the flow field in this length scale (an excellent review can be found on the physics of fluid flow at microscale in [1]). A microfluidic rotary pump, which is proposed by Sen et al. [2], is a device that is used for pumping fluids in microfluidic applications at extremely low Reynolds number. This miniature device consists of a rotating cylinder placed eccentrically inside a microchannel where the axis of the cylinder is perpendicular to the flow direction (see Fig. 1). Since it is placed asymmetrically, there exists a viscous resistance difference between the small and large gaps between the cylinder and the walls (i. e. unequally distributed shear force on the upper and lower surface of the rotating cylinder), which causes a net flow along the channel. They are capable of pumping very small flow rates which is desired for many medical and biological applications such as drug delivery.