Establishing the suitability of 3D-printed devices for low-temperature geochemical experiments

Abstract

Desktop 3D printing stereolithography (SLA) is a fabrication technique based on photopolymerization that can be used to efficiently create novel reaction devices for laboratory geochemistry with complex features (e.g. internal channels, small volumes) that are beyond the capabilities of traditional machining methods. However, the stability of 3D printed parts for low-temperature aqueous geochemical conditions has not been carefully evaluated. Furthermore, it is unclear what criteria should be used when attempting to optimize the mechanical and chemical properties during post-processing steps. Addressing these challenges is important for determining the suitability of 3D printed devices for laboratory investigations such as mineral precipitation/dissolution experiments. Here, we use thermogravimetric analysis (TGA) profiles, dynamic mechanical analysis (DMA), and chemical extraction of leachables to show how ultraviolet (UV) post-curing can optimize properties of a commercial photo-reactive resin (Formlabs Standard Clear). The mechanical and chemical stability of the post-cured material was enhanced and a working temperature of up to 80 °C was determined. We further provide data showing the stability and compatibility of the material in aqueous conditions of pH 0, 5.7 and 12. As SLA 3D printing is still an emerging and rapidly developing technology, the method presented here will provide a framework for assessing how new printer types and materials (i.e. resins) impact the suitability of SLA printed devices for future experimental studies.