Supporting data for "3D Printed Self-Supporting Elastomeric Structures for Multifunctional Microfluidics"

Abstract

Microfluidic devices fabricated via soft lithography have demonstrated compelling applications in areas such as rapid biochemical assays, lab-on-a-chip diagnostics, DNA microarrays and cell analyses. These technologies could be further developed by directly integrating microfluidics with electronic sensors and curvilinear substrates as well as reducing the human-centric fabrication processes to improve throughput. Current additive manufacturing methods, such as stereolithography and multi-jet printing, tend to contaminate substrates due to uncured resins or supporting materials that are subsequently evacuated to create hollow fluid passages. Here we present a printing methodology based on precisely extruding viscoelastic inks into self-supporting structures, creating elastomeric microchannels and chambers without requiring sacrificial materials. We demonstrate that, in the sub-millimeter regime, the yield strength of the as-extruded silicone ink is sufficient to prevent creep under the gravitational loading within a certain angular range. Printing toolpaths are specifically designed to realize leakage-free connections between channels and chambers, T-shaped intersections and overlapping channels. The self-supporting microfluidic structures enable the automatable fabrication of multifunctional devices, including multi-material mixers, microfluidic-integrated sensors, automation components and 3D microfluidics.