Wavelength-Dependent 3D Printing: Introducing 3D Printed Action Plots.

Abstract

Light-driven additive manufacturing is a key technology that relies on the ability of photons to effectively initiate the curing of a photoresin. We have previously demonstrated via photochemical action plots that irradiating a chromophore at its maximum wavelength of absorption does not necessarily lead to a photochemical process with the highest efficiency. Today, action plots are considered a powerful methodology to access wavelength-resolved photochemical reactivity. However, there is currently no study that translates the knowledge gained from solution-based photopolymerization action plots to light-driven 3D printing. Herein, we investigate the reactivity of a photoresin system and the formation of a cured polymer network using a stereolithography 3D printing set-up coupled with a monochromatic wavelength tunable laser system, carefully determining the effect of disparate monochromatic wavelengths on the printing outcome in analogy to solution photochemical action plots. We find that although the reactivity of the resin used herein, and subsequent material properties, are not fully aligned with the solution action plot of the solution photopolymerization using the same photoinitiator, a 3D Printed Action Plot (3D-PAP) revealed that curing the photoresin at longer wavelengths results in efficient 3D printing and superior mechanical properties in line with the red-shifted highest reactivity observed for the solution photopolymerization.