Dresden 2011 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 29: Posters: Biopolymers \& Biomaterials
BP 29.14: Poster
Donnerstag, 17. März 2011, 17:15–20:00, P3
Cyclic contraction of regenerated Bombyx mori silk fibroin nanofibers — Taiyo Yoshioka1, Aurel Radulescu2, Yutaka Kawahara3, and •Andreas Schaper1 — 1Center for Materials Science, Philipps University, 35032 Marburg, Germany — 2Department of Biological and Chemical Engineering, Gunma University, Gunma 376-8515, Japan — 3Jülich Centre for Neutron Science at FRM II, 85747 Garching, Germany
Spider dragline silk is known to show significant shrinking (supercontraction) when the fiber is wetted under unrestrained conditions, restraining generates substantial stress (ca. 50MPa) accordingly. In addition to the irreversible supercontraction, a reversible (cyclic) relaxation-contraction response to wetting and drying has been found. By contrast, similar supercontraction has so far not yet been observed in natural Bombyx mori silk, but occurred in regenerated silk when a special spinning regime was applied.
We report first observations of cyclic contraction by EtOH and water vapour treatment of electrospun nanofibers of regenerated Bombyx mori silk fibroin. Mechanical measurements and time-resolved microscope observations showed that the contraction behavior is significantly influenced by the structural state of the original fibers. This was proved by scanning and transmission electron microscopy and diffraction, wide-angle x-ray diffraction and small-angle neutron scattering. From our observations we derived a tentative model of the irreversible and the cyclic contraction mechanisms.
T.Y. is grateful to AvH Foundation for a fellowship.