Sacrificial ionic bonds need to be randomly distributed to provide shear deformability.
Multivalent ions are known to allow for reversible cross-linking in soft biological materials, providing stiffness and extensibility via sacrificial bonds. We present a simple model where stiff nanoscale elements carrying negative charges are coupled in shear by divalent mobile cations in aqueous media. Such a shear coupling through a soft glue has, indeed, been proposed to operate in biological nanocomposites. While the coupling is elastic and brittle when the negative charges are periodically arranged, sufficient randomness in their distribution allows for large irreversible deformation.
Hartmann
Markus A
MA
Institute of Physics, University of Leoben, Franz-Josef Strasse 18, A-8700 Leoben, Austria.
Fratzl
Peter
P
D001696:Biomechanical Phenomena; D007477:Ions; D008954:Models, Biological; D055672:Static Electricity; D013499:Surface Properties
D007477:Ions