Additive Manufacturing of Micro-Architected Copper based on an Ion-Exchangeable Hydrogel

Additive manufacturing (AM) of copper through laser-based processes poses challenges, primarily attributed to the high thermal conductivity and low laser absorptivity of copper powder or wire as the feedstock. Although the use of copper salts in vat photopolymerization-based AM techniques has garnered recent attention, achieving micro-architected copper with high conductivity and density has remained elusive. In this study, we present a facile and efficient process to create complex 3D micro-architected copper structures with superior electrical conductivity and hardness. The process entails the formulation of an ion-exchangeable photoresin, followed by the utilization of digital light processing (DLP) printing to sculpt 3D hydrogel scaffolds, which were transformed into Cu²⁺-chelated polymer frameworks (Cu-CPFs) with a high loading of Cu²⁺ ions through ion exchange, followed by debinding and sintering, results in the transformation of Cu-CPFs into miniaturized copper architectures. This methodology represents an efficient pathway for the creation of intricate micro-architected 3D metal structures.