Simple Method for Photopatterning Commercial PDMS Using an Off-the-Shelf Photodeactivated Hydrosilylation Inhibitor

This paper describes a method of micropatterning commercial silicone elastomers using a photodeactivated hydrosilylation inhibitor. The method uses small doses of 365 nm light and is compatible with common platinum-cured formulations of poly(dimethylsiloxane) (PDMS). The hydrosilylation (cross-linking) inhibitor is a UV-sensitive emulsion composed of FeCl3 and a commercially available poly(ethylene oxide)-co-PDMS copolymer. This mixture enables selective solidification of exposed regions while preventing solidification in unexposed areas. This approach facilitates the creation of complex geometries while preserving the mechanical tunability, biocompatibility, and optical transparency of the base silicone. The patterned structures have been successfully used to fabricate high-resolution microfluidic devices and substrates for measuring the contractility of cardiac cells with integrated strain gauges. The process achieves feature sizes as small as 20 μm and is compatible with standard photolithography tools.