Regensburg 2013 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 17: Biomaterials and Biopolymers II (joint with CPP)
BP 17.8: Vortrag
Mittwoch, 13. März 2013, 11:45–12:00, H43
Thermal vibrations reduce the efficacy of sacrificial bonds — •Soran Nabavi1, Matthew J. Harrington2, Peter Fratzl2, Oskar Paris1, and Markus A. Hartmann1 — 1Institute of Physics, Montanuniversitaet Leoben, Leoben, Austria — 2Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Potsdam, Germany
Mussel byssal threads are a fascinating biological material combining high stiffness, toughness and extensibility. Experimental studies suggest that these outstanding properties are achieved by using so called sacrificial bonds (SBs) which are weaker than the covalent bonds holding the structure together and that can form and open reversibly [1]. The SBs break before the covalent bond rupture, providing hidden length and allowing for efficient energy dissipation.
In this study computer simulations are used to investigate the effect of SBs on the mechanical properties of a single polymeric chain. Special emphasis was put on the interplay of covalent and sacrificial bonds and the effect of thermal vibrations that have been largely overlooked in the description of SBs so far. In a simple setting with only one SB it is found that molecular chain fluctuations reduce the efficacy of SBs. Even for SBs with rather high binding energies of ~1 eV backbone fluctuations lead to a rupture of SBs before external loading sets in. Thus, the theoretical strength of SBs is reduced more than a factor of two. This effect increases with increasing polymeric chain length and with increasing temperature.
[1] M. J. Harrington et al., J. Struct. Biol. 167, 47 (2009)