Coordination polymers (CPs) and coordination network solids such as metal-organic frameworks (MOFs) have gained increasing interest during recent years due to their unique properties and potential applications. Preparing 3D printed structures using CP would provide many advantages towards utilization in fields such as catalysis and sensing. So far, functional 3D structures were printed mostly by dispersing pre-synthesized particles of CPs and MOFs within a polymerizable carrier. This resulted in a CP active material dispersed within a 3D polymeric object, which may obstruct or impede the intrinsic properties of the CP. Here, we present a new concept for obtaining 3D free-standing objects solely composed of CP material, starting from coordination metal complexes as the monomeric building blocks, and utilizing the 3D printer itself as a tool to in situ synthesize a coordination polymer during printing, and to shape it into a 3D object, simultaneously. To demonstrate this, a 3D-shaped nickel tetra-acrylamide monomeric complex composed solely of the CP without a binder was successfully prepared using our direct print-and-form approach. We expect that this work will open new directions and unlimited potential in additive manufacturing and utilization of CPs.

By designing an actuator composed of thin layers with different coefficients of thermal expansion (CTE) together with an electrically conductive layer, the CTE mismatch can be utilized to produce soft electrothermal actuators (ETAs). These actuators have been typically implemented using only two layers, commonly relying on Timoshenko's analytic model that correlates the temperature to the actuator's curvature. In this study, we extend the analytic model to include the thermoelectric relation present in ETAs, that is, the conductive layer's properties with respect to the operation temperature. By applying the thermoelectric relation, a minimal voltage optimization can be applied to the analytic model. Using dimensionless analysis, we optimize the ETAs performance for both bi- A nd tri-layer ETAs with and without the thermal modeling. The bi-layer optimization not only predicts the maximal value for the bi-layer performance but also provides the optimal thickness of each layer for any couple of materials. We validate the tri-layer analytic model experimentally by measuring the curvature for different third layer thicknesses. Finally, we optimize the tri-layer design based on the analytic model, which can achieve an improvement in curvature per voltage of >3000% over the optimal bi-layer ETA.