Two Fundamental Mechanisms Govern the Stiffening of Cross-linked Networks

Goran Zagar, Patrick R. Onck, Erik van der Giessen*

*Bijbehorende auteur voor dit werk

OnderzoeksoutputAcademicpeer review

55 Citaten (Scopus)
216 Downloads (Pure)

Samenvatting

Biopolymer networks, such as those constituting the cytoskeleton of a cell or biological tissue, exhibit a nonlinear strain-stiffening behavior when subjected to large deformations. Interestingly, rheological experiments on various in vitro biopolymer networks have shown similar strain-stiffening trends regardless of the differences in their microstructure or constituents, suggesting a universal stiffening mechanism. In this article, we use computer simulations of a random network comprised of cross-linked biopolymer-like fibers to substantiate the notion that this universality lies in the existence of two fundamental stiffening mechanisms. After showing that the large strain response is accompanied by the development of a stress path, i.e., a percolating path of axially stressed fibers and cross-links, we demonstrate that the strain stiffening can be caused by two distinctly different mechanisms: 1) the pulling out of stress-path undulations; and 2) reorientation of the stress path. The former mechanism is bending-dominated and can be recognized by a power-law dependence with exponent 3/2 of the shear modulus on stress, whereas the latter mechanism is stretching-dominated and characterized by a power-law exponent 1/2. We demonstrate how material properties of the constituents, as well as the network microstructure, can affect the transition between the two stiffening mechanisms and, as such, control the dominant power-law scaling behavior.

Originele taal-2English
Pagina's (van-tot)1470-1479
Aantal pagina's10
TijdschriftBiophysical Journal
Volume108
Nummer van het tijdschrift6
DOI's
StatusPublished - 24-mrt-2015

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