Synthesis and mechanical performance characterization of nanocomposite scrolls closely mimicking sponge spicules
Final Report Abstract
The overall aim of this project was to realize ceramic-based scrolls whose architecture closely mimics the structure of natural sponge spicules, and explore their application potential especially as actuators. During the second period, the focus was on optimizing the fabrication and mechanical stability of the scrolls, as well as investigating their response to humidity or magnetic fields. By optimizing the relevant parameters, we succeeded in significantly increasing the speed and precision of scroll fabrication via the razor-blade technique developed in the first period. This technique could not only be extended to hybrid films composed of materials of different stiffness, but also to fabricate entire arrays of scrolls at predefined positions. Significant progress could also be made by improving the mechanical properties and structural integrity of V2O5 scrolls by filling their central channel with inorganic (TiO 2) or organic polymer nanoparticles. In the latter case, the use of a specifically adapted ice-templating procedure ensured complete filling of lamella spaces. This enabled an impressive, up-to eightfold increase in maximum load due to an effective stress distribution and energy dissipation, in close analogy to the fracture behavior of natural sponge spicules. As another notable advancement, magnetic Fe3O4 nanoparticles could be smoothly integrated into V2O5 and cellulose nanofiber films. Controlled scrolling of such hybrid films, whose microstructure was optimized via adjusting nanoparticle concentration and distribution, yielded scrolls with robust mechanical stability and efficient magnetic responsiveness. Besides magnetic actuators, we could also demonstrate efficient humidity-driven actuation, with excellent control of the response speed by the scroll curvature, for scrolls obtained from V2O5/cellulose hybrid films. The achievements made open up novel and promising application perspectives in various fields. Firstly, the developed razor-blade technique for scrolling is outstanding in several respects, such as an extraordinary scrolling speed of 1 mm/s, an aspect ratio exceeding 600 for the resulting scrolls, a scroll length of up to 30 mm, and the possibility to implement a spiral geometry. Secondly, the realized hybrid scrolls combining two or more different types of film are very useful for energy storage (rechargeable batteries) and micro-robotics, where compact and efficient designs with a small footprint are crucial. Thirdly, the demonstrated magnetic actuators combining rapid response with high mechanical stability and durability, are excellently for magnetic actuation technologies, including helical coils that require reduced operation power.
Publications
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A straightforward method for scrolling planar materials into free-standing 3D structures, 7th Conference of the Serbian Society for Ceramic Materials, June 14-16. 2023, Belgrade, Serbia
Diem, A. M.; Bill, J. & Burghard, Z.
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Fast One‐Step Fabrication of Highly Regular Microscrolls with Controllable Surface Morphology. Advanced Science, 10(21).
Diem, Achim M.; Bill, Joachim & Burghard, Zaklina
