A novel method to prepare copper microspheres via chemical reduction route

Copper, due to its high electrical conductivity, catalytic, and antimicrobial activity, is widely used in various applications. Also, the abundance of copper and its low cost make it a suitable alternative to Ag or Au for commercial application. Monodispersed spherical copper particles with average particle sizes of around 1.0 μm are currently required for microelectronics application, particularly, for the fabrication of conductive materials for additive manufacturing. These particles are currently produced only by means of various physical methods, which require very expensive equipment, a significant amount of feedstock materials, and the subsequent stages of sieving using complex classifiers. In addition, most of the feedstock materials goes to waste when selecting the fractions of a specified size range. On the other hand, when using wet-chemical synthetic methods, copper nanoparticles and micron-sized polyhedra are mostly obtained. In this study, we have prepared monodispersed, micron-sized spherical copper and cuprous oxide particles with well-defined morphology by the reduction of copper 2-[2-(2-methoxyethoxy)ethoxy]acetate with benzyl alcohol at 195°С. The method developed is simple, low cost and highly scalable. Importantly, the size and spherical shape of copper particles were successfully achieved by controlling the size and morphology of Cu2O which is an intermediate towards the formation of Cu particles. The as-synthesized copper powders may have applications as metallic fillers in ink and paste formulations for 2D and 3D micro-printing to fabricate functional components and devices.