Using serrated edges to control fluid front motion in microfluidic devices

Abstract

The traversal rate for the liquid medium near a microfluidic channel edge is faster than that through the body of the channel, which makes the fluid front becomes concave rather than convex or flat. The concave front is unwished due to its influences on quantitative analysis accuracy and the possibility to generate air bubbles which will do harm to analysis process. Here, a method which can control the shape of fluid front in a microfluidic channel is presented. The channel edges that are parallel to the direction of flow are designed to three types of serrated shapes, including semicircle, triangle and trapezoid. The effects of their length ratio (r), peak distance (w) and phase mode (p) on meniscus curvature and flowing speed have been studied. Results have shown that the channel with serrated edges can generate convex fluid front, and the curvature of the fluid front as well as the flowing speed can be changed by adjusting r, w and p.