Enabling stress-free polymer 3D printing

Modulating metal-ligand interactions in metallopolymers allows tuning the mechanical response of metallopolymers and provides a platform for understanding the connection between the reversible nature of the crosslinks and the macroscale mechanical properties. We present nickel(II) carboxylate as a tunable, reversible crosslinking interaction in UV curable metallopolymers. Different numbers and types of neutral ligands that coordinate to the metal center are introduced as a straightforward approach to modulate the strength of the ionic interactions in the nickel carboxylate crosslinks and allow macroscale mechanical properties to be tuned. The ability of the reversible crosslinking interactions to break and reform enables the relief of the residual stress generated during the curing process, thus allowing the 3D printing of polymer structures that boast higher spatial accuracy and superior mechanical properties.