Soft microflow sensors

Abstract

We present a rapid prototyping method for integrating functional components in conventional PDMS microfluidic devices. We take advantage of stop-flow lithography (D. Dendukuri, S. S. Gu, D. C. Pregibon, T. A. Hatton and P. S. Doyle, Lab Chip, 2007, 7, 818)¹ to achieve the in situ fabrication of mobile and deformable elements with a controlled mechanical response. This strategy is applied to the fabrication of microflow sensors based on a deformable spring-like structure. We show that these sensors have a large dynamic range, typically 3 to 4 orders of magnitude, and that they can be scaled down to measure flows in the nl per min range. We prepared sensors with different geometries, and their flow-elongation characteristics were modeled with a simple hydrodynamic model, with good agreement between model and experiments.