Dresden 2011 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 2: Biopolymers and Biomaterials I (jointly with BP)
CPP 2.2: Vortrag
Montag, 14. März 2011, 11:00–11:15, ZEU 222
Structure-property relationships of natural silk fibers as studied by time-resolved Fourier-Transform Infrared Spectroscopy (FTIR) — •Roxana Ene1, Periklis Papadopoulos2, and Friedrich Kremer1 — 1Institüt für Experimentelle Physik I, Leipzig, Germany — 2Max-Planck- Institut für Polymerforschung, Mainz, Germany
Polarized IR-spectroscopic and mechanical measurements are combined to analyse the conformational changes in hydrogenated and partially deuterated major ampullate spider silk of Nephila edulis[1].Crystal stress can be measured from the frequency shift of main-chain vibrations. The results show that in both states of silk a serial arrangement between the crystalline and amorphous phase dominates the nanostructure. The determination of the molecular order parameters of the different moieties proves that the amide hydrogen exchange is a selective process, taking place at the surface of β-sheet nanocrystals, implying that these regions are accessible by water[2].The mechanical properties are changing dramatically when the fiber is wet due to the fact that the pre-stress of the chains interconnecting the nanocrystals is irreversibly released. A three-component combined model of crystals in serial arrangement with amorphous chains and a fraction of chains bypassing them can describe all aforementioned states of spider silk[3]. [1] P. Papadopoulos, R. Ene, I. Weidner, F. Kremer Macromol. Rapid Commun 30,(2009). [2] R.Ene, P. Papadopoulos, F. Kremer Polymer 51,(2010) [3] R. Ene, P. Papadopoulos, F. Kremer, Soft Matter 5 (2009)