(235d) High-Resolution Stereolithography: Negative Spaces Enabled By Control of Fluid Mechanics

Stereolithography enables the fabrication of three-dimensional (3D) freeform structures via light-induced polymerization. However, the accumulation of UV dose within resin trapped in negative spaces, such as microfluidic channels or voids, can result in the unintended closing, referred to as overcuring, of these negative spaces. We report the use of injection continuous liquid interface production (iCLIP) to continuously displace resin at risk of overcuring in negative spaces created in previous layers with fresh resin to mitigate the loss of Z axis resolution. We demonstrate the ability to resolve 50 mm microchannels, breaking the historical relationship between resin properties and negative space resolution. Using the iCLIP approach, we fabricated proof-of-concept 3D free-form microfluidic devices with improved design freedom over device material selection and resulting properties for applications ranging from microneedle drug delivery to advances separations.