3D printing of multifunctional metal oxides via a novel photopolymer system

Abstract

In recent years, 3D printing of ceramics has become a significant area of interest as it has the potential to remove the geometrical limitations assocd. with the current state of the art of ceramic processing. In particular, processes involving photolithog. are esp. promising due to the high resoln. and small feature sizes achievable.These photolithog. systems typically consist of photosensitive slurries, where fine powders of the desired ceramic of choice are dispersed in a photosensitive org. binder. By selectively exposing certain parts of the slurry, a green body can be made. A subsequent high temp. treatment then burns off the org. binder and sinters together the remaining ceramic powders into a dense ceramic part.The advantages of these systems are that it's simple and versatile - as long as the desired ceramic can be obtained in powder form and can be dispersed in the binder, the slurry can be obtained and the part 3D printed. However, the slurry often has to have a high loading of ceramic particles, which increases the viscosity and refractive index of the slurry, making it difficult to print with. In this presentation, a new photopolymer system that circumvents the problems of powder loading is demonstrated. As an example of this technique, we demonstrate the printing of zinc oxide (ZnO) architected structures. ZnO is traditionally deposited as films and can only be made 3D via a multistep process that involves depositing a thick layer of ZnO and then using an ion-mill to cut out the structure desired. Here, we show a two-step process to fabricate monolithic ZnO structures out of any arbitary design. Characterization of these structures verify that the structures are indeed zinc oxide. Compression of these materials also results in a voltage response, showing the piezoelec. behavior of these structures.