Robocasting of porous alumina hollow fibre monoliths by non-solvent induced phase inversion

Abstract

3D printed hollow fibre structures are of interest for different separation processes. However, the preparation of such structures using robocasting is not evident due to their poor self-supporting properties after printing. We propose a method based upon non-solvent induced phase inversion to overcome this issue, and use this method for preparing porous alumina hollow fibre structures. The method uses a paste that contains alumina powders, polyetherimide as polymeric binder and N-Methyl-2-pyrrolidone as solvent, that is extruded through a concentric nozzle. A humid atmosphere is used to further solidify these extruded hollow fibres enabling the printing of both hollow 2D patterns and 3D monolithic structures. The resulting green samples are mechanically strong and can be easily handled without any shape deformation before thermal treatment