Macroporous alumina scaffolds consisting of highly microporous hollow filaments using three-dimensional ceramic/camphene-based co-extrusion

This study proposes a novel type of macroporous ceramic scaffolds, which are comprised of hollow tubular filaments with a highly microporous structure, using 3-dimensional ceramic/camphene-based co-extrusion (3D-CoEx). The use of an initial feedrod, comprised of a camphene core and an alumina/camphene shell, enabled the construction of hollow tubular frameworks and micropores through the removal of the camphene phase. The produced scaffolds showed 3-dimensionally interconnected macropores with dimensions of ∼250-300 μm × 400-550 μm, which were surrounded by hollow alumina filaments (∼500 μm in diameter) featuring a number of micropores (several tens of microns in size). This unique macro/micro-porous structure could achieve a combination of both the reasonably high compressive strength of ∼5.4 MPa and very high porosity of 86 vol%. In addition, the final mechanical properties and overall porosity of the porous alumina scaffolds could be fine-tuned by adjusting initial alumina content in the alumina/camphene.