Incorporating steric hindrance into the additive design enables a robust formulation of alumina ink for extrusion-based 3d printing

The capabilities of additive manufacturing for fabrication of complex and thin-walled ceramic-based objects are restricted by the availability of ceramics inks. Formulations of current ink systems strictly depend on using high content of organic additives (5–30 wt. %). The high amounts of additives affect uniformity and dimensional accuracy of the final object. Here, for the first time in literature, we designed a single additive that enables printing of high aspect ratio, thin-walled structures (height/width = 58) and complex geometries from an ink of alumina nanoparticles that comprises very low organic content (i.e., 1.25 wt. % of nanoparticles mass). In addition to generally exploited electrostatic effect, this additive has purpose-driven tailoring to harness steric hindrance to control the viscoelastic response of ceramic suspensions and realize an optimum ink for extrusion-based 3D printing. We pursued a step-wise approach in developing such an additive through synthesis of series of copolymers with...