Method to fabricate round cross-sectional channel using thermal expansion of air for passive flow regulators

We present a novel method for fabricating round cross-sectional channels for autoregulatory pressure regulators. The application of previously reported methods in multilayered soft lithography using three-dimensional printed molds is challenging. Herein, we used a thermal expansion technique to create round cross-sectional channels in replica layers using air in the cavity space of a master mold. The width and height of the round channel in the replica could be adjusted in the range of 80-300 and 3-57 & mu;m, respectively, by varying the precuring time of the replica in the gel state and adjusting the cavity size of the master mold. We successfully fabricated a pressure regulator with a round cross-sectional channel, achieving a constant output pressure at a low threshold input pressure. Our device exhibited superior performance, with a constant output pressure at a threshold input pressure of less than 77%, compared to a device with a rectangular cross-sectional channel. Our method has significant potential for application in the fabrication of integrated microfluidic systems with round cross-sectional channels.

Automated summary

We propose a novel method for fabricating round cross-sectional channels for autoregulatory pressure regulators. By using a thermal expansion technique, we can create round channels in replica layers using air in the cavity space of a master mold. Our method allows for adjustable width and height of the channels, ranging from 80-300 μm and 3-57 μm, respectively. Compared to devices with rectangular channels, our pressure regulator with a round channel achieves constant output pressure at a lower threshold input pressure of less than 77%.