Fabricating Microchannels in Elastomer Substrates for Stretchable Electronics

As flexible devices and machines become more ubiquitous, there is a growing need for similarly deformable electronics. Soft polymers continue to be widely used as stretchable and flexible substrates for soft electronics, and in particular, soft sensing. These soft sensors generally consist of a highly elastic substrate with embedded microchannels filled with a conductive fluid. Deforming the substrate deforms the embedded microchannels and induces a change in the electrical resistance through the conductive fluid. Microchannels, thus, are the foundation of flexible electronic devices and sensors. These microchannels have been fabricated using various methods, where the manufacturing method greatly impacts device functionality. In this paper, comparisons are made between the following methods of microchannel manufacturing: cast molding, 3D printing of the elastomer substrate itself, and laser ablation. Further processing of the microchannels into flexible electronics is also presented for all three methods. Lastly, recommended ranges of microchannel sizes and their associated reproducibility and accuracy measures for each manufacturing method are presented.