Research Team Bends Individual Nanostructures

Aerographite’s complex tetrapodal architecture gives the material its unique properties. For the first time, a research team at Kiel University (Christian-Albrechts-Universität zu Kiel, CAU) were able to fold the individual tetrapods measuring only a few micrometres.

A research group at Kiel University and the Hamburg University of Technology developed aerographite, one of the most lightweight materials in the world, a few years ago and have continued their research on it since then. Aerographite is formed of tetrapods, which are carbon-based 3D nanostructures each consisting of four hollow arms. When combined together, they form a porous, extremely lightweight network, resulting in a weight of only 0.2 milligrams per cubic centimetre for aerographite. "Because of this unique structure, the material exhibits a high mechanical strength, as well as a comparatively large surface area, from which interesting physical and chemical features originate", says Daria Smazna, a doctoral student in the project.

The international research team led by Kiel has now managed to demonstrate that aerographite’s individual arms can be bent reversibly at different places. "They automatically go back to their original shape, without sustaining any damage", explains Dr. Yogendra Mishra, materials scientist in the working group "Functional Nanomaterials" at Kiel University: "Just like an accordion, the three-dimensional object can be folded into a two-dimensional form, and then unfolded again." A special scanning electron microscope in Riga, Estonia, provided the evidence that their model also worked in practice. With a nanoscale measuring needle, their colleagues in Riga were able to grasp and bend the aerographite tetrapods.

"The calculation method, which has been developed and verified because of this international cooperation, can be applied to tetrapods in various sizes. It provides a valuable basis for investigating the properties of whole tetrapod networks and aerographite even further", Mishra explains. Understanding how networks of hollow tetrapods can be folded arbitrarily without sustaining damage may make sophisticated applications both in materials science and in regenerative medicine possible.