Berlin 2015 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 54: Biomaterials and Biological Materials IV

MM 54.3: Talk

Thursday, March 19, 2015, 12:15–12:30, TC 006

The influence of reversible cross-links on the mechanical properties of chain-bundle systems — •S. Soran Nabavi and Markus A. Hartmann — Institute of Physics, Montanuniversität Leoben, Leoben, Austria

Although biological materials use a very limited number of base elements to build their structures, these structures show an enormous diversity of mechanical properties. One effective strategy to increase the toughness of these materials is using reversible cross-links in their structures. These so called sacrificial bonds can be found in a large variety of biological materials e.g. bone, wood and in softer fibers like silk and byssal threads. We use Monte Caro simulations to examine the influence of grafting density and cross-link density on the mechanical properties of the chain bundle by determining load-displacement curves. Most surprisingly the results show that only two cross-links are sufficient to break the backbone of the system although the cross-links are weaker than the covalent bond by factor of four. This failure is caused by the topology of the interchain cross-links in the chain bundle where sacrificial bonds are distributed in an ordered arrangement. This backbone failure weakens the strength of the material, but increases the amount of work to elongate the system as well as the apparent stiffness of the bundles. These results bear important implications for the understanding of natural systems and for the generation of strong and ductile biomimetic polymers.