Direct ink writing of geopolymeric inks

The development of geopolymeric inks with optimized rheological properties for DIW is presented; several inks with different water content and additives were compared to determine which parameters enable extrusion as well as shape retention. It is a challenging task, because the inks are subjected to ongoing poly-condensation reactions which continuously modify their rheological properties over time. Highly porous ceramic lattices (porosity up to ∼71 vol%) were fabricated with ∼0.8 mm struts and unsupported features with very limited sagging. Their physical and mechanical properties were characterized and correlated. Our approach can be successfully extended to other formulations. Geopolymeric foams have recently been proven as suitable for water filtration; the use of precisely designed, non stochastic printed structures could enhance the mechanical properties of the porous components, provide a better control of pressure drop and fluid dynamics inside the part and improve their performances consistently.