Additive manufacturing using highly concentrated nanocolloids of metal hydroxide salts towards structured metals and metal oxides

Additive manufacturing by vat-photopolymerization is important technique to prepare designed objects because of its features of availability, low cost, low energy consumption, and high-speed printing. One of the major challenges of this technique is how to expand the chemical composition towards metals and ceramics in addition to organic compounds. In this paper, we report synthesis of highly concentrated nanocolloids of nickel hydroxide acrylate and use them for vat-photopolymerization. Epoxide-mediated basification induced formation of dispersed nickel hydroxide acrylate monolayer/bilayer nanoparticles (diameter of 2.31 nm). The concentration of nanocolloid was prepared as 2.5 mol L−1 (Ni basis), which corresponds to 43 wt % and 30 vol %. The concentrated nanocolloids enabled to produce objects through vat-photopolymerization by using commercially available 3D printers. Addition of small quantity of organic cross-linker efficiently interconnect nanoparticles to form bulky objects. Owing to the organic moiety of nickel hydroxide salt nanoparticles, metal/carbon composites formed by heat-treatment without any reduction gas supply. Further heat-treatment led metal oxide bulky object with macroporous structure.