Graphene Oxide Based Transparent Resins For Accurate 3D Printing of Conductive Materials

Digital Light Processing (DLP) allows the fast realization of 3D objects with high spatial resolution. However, DLP is limited to transparent resins, and therefore not well suited for printing electrically conductive materials. Manufacturing conductive materials will significantly broaden the spectrum of applications of the DLP technology. But conductive metals or carbon-based fillers absorb and scatter light; inhibiting thereby photopolymerization, and lowering resolution. In this study, UV transparent liquid crystal graphene oxide (GO) is used as precursor for generating in situ conductive particles. The GO materials are added to a photopolymerizable resin via an original solvent exchange process. By contrast to earlier contributions, the absence of drying during the all process allows the GO material to be transferred as monolayers to limit UV scattering. The absence of UV scattering and absorption allows for fast and high-resolution 3D printing. The chosen resin sustain high temperature to enable an in situ efficient thermal reduction of GO into reduced graphene oxide (rGO) that is electrically conductive. The rGO particles form percolated networks with conductivities up to 1.2 x 10(-2) S m(-1). The present method appears therefore as a way to reconcile the DLP technology with the manufacturing of 3D electrically conductive objects.

Automated summary

Digital Light Processing (DLP) technology enables fast and high-resolution 3D printing, but it is limited to transparent resins and not suitable for printing conductive materials. In this study, a UV transparent liquid crystal graphene oxide precursor is used to generate in situ conductive particles in a photopolymerizable resin. The resin can sustain high temperature for the thermal reduction of graphene oxide into electrically conductive reduced graphene oxide particles. This method reconciles the DLP technology with the manufacturing of 3D electrically conductive objects.