title: Frequency-dependent stiffening of semiflexible networks: a dynamical nonaffine to affine transition.
abstract: By combining the force-extension relation of single semiflexible polymers with a Langevin equation to capture the dissipative dynamics of chains moving through a viscous medium we study the dynamical response of cross-linked biopolymer materials. We find that at low frequencies the network deformations are highly nonaffine, and show a low plateau in the modulus. At higher frequencies, this nonaffinity decreases while the elastic modulus increases. With increasing frequency, more and more nonaffine network relaxation modes are suppressed, resulting in a stiffening. This effect is fundamentally different from the high-frequency stiffening due to the single-filament relaxation modes [F. Gittes and F. C. MacKintosh, Phys. Rev. E 58, R1241 (1998)], not only in terms of its mechanism but also in its resultant scaling: G'(ω) ∼ ω(α) with α > 3/4. This may determine nonlinear material properties at low, physiologically relevant frequencies.
authors.affiliation: Instituut-Lorentz, Universiteit Leiden, Postbus 9506, NL-2300 RA Leiden, The Netherlands.
authors.forename: E M
authors.initials: EM
authors.lastname: Huisman
authors.forename: C
authors.initials: C
authors.lastname: Storm
authors.forename: G T
authors.initials: GT
authors.lastname: Barkema
mesh_terms: D001704:Biopolymers / Q000737:chemistry*; D004548:Elasticity; D055595:Mechanical Phenomena; D008958:Models, Molecular; D008968:Molecular Conformation
chemical_list: D001704:Biopolymers