Harvard MIT ceramic foam ink
Harvard and MIT used ceramic foam ink to 3D-print lightweight hexagonal and triangular honeycombs, which also boasted tunable geometry and density.
Two Engineering departments at Harvard University have collaborated with MIT to develop a new method to 3D-print materials with significant absorbency using a ceramic foam ink.
The Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and the Harvard Wyss Institute for Biologically Inspired Engineering led the research project and eventually successfully produced materials with independently tunable macro and microscale porosity.
Published in the Proceedings of the Natural Academy of Science, the researchers believe their approach could be used to fabricate lightweight structural materials, thermal insulation or tissue scaffolds. Expanding the compositional space of printable materials, the researchers were able to produce lightweight materials, which remained stiff. This process was helped by the use of ceramic foam ink, which contains alumina particles, water and air.
“Foam inks are interesting because you can digitally pattern cellular microstructures within larger cellular macrostructures,” said Joseph Muth, a graduate student in Harvard’s Lewis Lab and first author of the paper. “After the ink solidifies, the resulting structure consists of air surrounded by ceramic material on multiple length scales. As you incorporate porosity into the structure, you impart properties that it otherwise would not have.
“We can now make multifunctional materials, in which many different material properties, including mechanical, thermal, and transport characteristics, can be optimised within a structure that is printed in a single step.”
During the research, Harvard and MIT used ceramic foam ink to 3D-print lightweight hexagonal and triangular honeycombs, which also boasted tunable geometry and density, as well as stiffness. By controlling the foam’s microstructure, the researchers adjusted the ink’s properties and monitored how it deformed on the microscale.
“This process combines the best of both worlds,” said Lorna Gibson, the Matoula S. Salapatas Professor of Materials Science and Engineering at the Massachusetts Institute of Technology, who co-authored the paper. “You get the microstructural control with foam processing and global architectural control with printing. Because we’re printing something that already contains a specific microstructure, we don’t have to pattern each individual piece. That allows us to make structures with specific hierarchy in a more controllable way than we could do before.”
