Droplet-Based Microfluidic Scheme for Complex Chemical Reactions

Liquid flow in microfluidic channels typically occurs at low Reynolds numbers, such that the flow is purely laminar [Solomon et al. 2003; Oddy et al. 2001]. As a consequence, two or more streams of miscible fluids flowing side-by-side only mix by diffusion. Such a mixing is very slow and it would be difficult to perform chemical reactions within the typical length scales respectively time scales used in standard microfluidic settings [Bruus et al. 2007; Stone et el., 2004; Teh et al., 2008]. Furthermore, the axial dispersion of concentration gradients parallel to the flow direction (Taylor dispersion [Taylor, 1954]) is a problem associated with the laminar flow in confined geometries due to the parabolic flow profile within microfluidic channels.