SBIR Phase I: Additive Manufacturing of Silicone Elastomers and Thermosets Using Freeform Reversible Embedding

The broader impact/commercial potential of this Small Business Innovation Research (SBIR) Phase I project is to radically expand the types of polymers that can be 3D printed. Thermosets such as silicones, epoxies, and urethanes are used across manufacturing because they have excellent chemical, physical, and mechanical properties, and they can be readily molded. The proposed technology will enable 3D printing of existing industrial thermosets without modifications using standard 3D printing technologies available in the market. The technology addresses an unmet need for industries including consumer electronics, automotive, aerospace, and medical device by enabling additive manufacturing of qualified thermoset materials for new applications such as improving the fit and comfort of wearable electronic devices, lightweighting mechanical components, and integrating sensors into flexible medical devices. This effort directly supports advancing national health and defense capabilities through new additive manufacturing capabilities. This Small Business Innovation Research (SBIR) Phase I is focused on 3D printing a wide range of previously unprintable or difficult-to-print thermally-cured, thermoset materials. The impact will be unlocking a method of 3D printing thermosets without geometric limits while maintaining dimensional accuracy across features as small as 50 µm, addressing unmet additive manufacturing needs within consumer electronics, automotive, aerospace, and medical device industries. While there are current 3D printers that can utilize photopolymerization to print specific resins, most engineering thermosets (e.g. silicones, epoxies, and urethanes) remain unprintable. This project will implement a scientific framework to understand polymer-solvent interactions during freeform reversible embedding of suspended hydrogels (FRESH) printing of thermoset inks within yield-stress support baths. In this process, liquid thermoset inks are extruded within a support bath where they are cured over time, making solubility, chemistry, and rheology critical success factors. Platinum-cured silicone is proposed as the initial candidate thermoset; the project will establish which block copolymers and solvents possess the right combination of solubility parameters to self-assemble into microgels that can be compacted to form the yield-stress support bath. FRESH printing process parameters will be optimized to achieve critical dimensional accuracy, resolution, fidelity, and mechanical properties of the printed parts. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.