A stretchable micromixer with enhanced performance for intermediate Reynolds numbers

Abstract

Chemical reactions in microscale require good mixing at a relatively low flowrate. However, mixing in microscale faces the major challenge of stable laminar flow associated with the low Reynolds number, the relative ratio between inertial force and viscous force. For low Reynolds numbers of less than unity, mixing occurs due to molecular diffusion. For high Reynolds number of more than several tens, chaotic advection enhances mixing. However, in the intermediate regime, mixing is not efficient. This paper reports a stretchable micromixer with dynamically tuneable channel dimensions. Periodically stretching the device changes the channel geometry and the curvature induced secondary Dean flows. The dynamically evolving secondary and main flows in the mixing channel result in chaotic advection and enhance mixing. The concept was demonstrated in a stretchable micromixer with a serpentine channel. We evaluated the performance of this stretchable micromixer both experimentally and numerically. At the intermediate range of Reynolds numbers from 4 to 17, the periodically stretched micromixer showed a better mixing efficiency than the non-stretched counterpart. Therefore, our stretchable micromixer is a potential candidate for applications where precious reagents need to be mixed at relatively low flow rate conditions.

On-demand deterministic release of particles and cells using stretchable microfluidics

“…This platform was custom-made, and the detailed manufacturing procedure has been elaborated in our previous work. 43 Briefly, the platform consisted of a linear translation stage connected to a stepper motor (JKM NEMA17 Two Phase 42 mm) controlled by an Arduino board. This motor and linear translation stage were arranged on a poly(methyl methacrylate) (PMMA) sheet that fits into the stage of an inverted microscope.…”

“…40 Elongating the stretchable microdevice allows precise tuning of the microchannel dimensions. [41][42][43] We designed and fabricated a stretchable microfluidic cell trapper that can be stretched along its width. The chip consists of an array of U-shaped microstructures with tiny gaps to trap and release particles and cells.…”