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MM: Fachverband Metall- und Materialphysik
MM 48: Topical session: In-situ Microscopy with Electrons, X-Rays and Scanning Probes in Materials Science V - Biological and Electronic Materials
MM 48.4: Vortrag
Donnerstag, 10. März 2016, 11:30–11:45, H38
Natural silk made optically switchable — •Igor Krasnov1, Nicolai R. Krekiehn1, Christina Krywka2, Urlich Jung1, Ahnaf U. Zllohu3, Thomas Strunskus3, Mady Elbahri2,3, Olaf M. Magnussen1, and Martin Müller1,2 — 1IEAP, Universität Kiel — 2Institute of Materials Research, HZG Geesthact — 3Institut für Materialwissenschaft, Universität Kiel
An optically active bio-material is created by blending natural silk fibers with photoisomerizable chromophore molecules-azobenzenebromide (AzBr). The material converts the energy of unpolarized light directly into mechanical work with a well-defined direction of action. The feasibility of the idea to produce optically driven microsized actuators on the basis of bio-material (silk) is proven. [1] The switching behavior of the embedded AzBr molecules was studied in terms of UV/Vis spectroscopy. To test the opto-mechanical properties of the modified fibers and the structural changes they undergo upon optically induced switching, single fiber X-ray diffraction with a micron-sized synchrotron radiation beam was combined in situ with optical switching as well as with mechanical testing and monitoring. The crystalline regions of silk are not modified by the presence of the guest molecules, hence occupy only the amorphous part of the fibers. It is shown that chromophore molecules embedded into fibers can be reversibly switched between the trans and cis conformation by illumination with light of defined wavelengths.
[1] I. Krasnov et al., Applied Physics Letters, 106, 093702 (2015)