Microstructure of Sheared Entangled Solutions of Semiflexible Polymers

Abstract

Abstract:We study the influence of finite shear deformations on the microstructure and rheology of solutions of entangled semiflexible polymers theoretically and by numerical simulations and experiments with filamentous actin. Based on the tube model of semiflexible polymers, we predict that large finite shear deformations strongly affect the average tube width and curvature, thereby exciting considerable restoring stresses. In contrast, the associated shear alignment is moderate, with little impact on the average tube parameters, and thus expected to be long-lived and detectable after cessation of shear. Similarly, topologically preserved hairpin configurations are predicted to leave a long-lived fingerprint in the shape of the distributions of tube widths and curvatures. Our numerical and experimental data support the theory.

Dynamics of Semiflexible Polymer Solutions in theTightly EntangledConcentration Regime

“…Hence, the need of new models that better account the contribution of the concentration-dependent characteristic length scales (e.g., L e ) of the polymer network to its mechanical properties. In this regard, it is worth mentioning that microscopy studies − on the tube width fluctuations in F-actin solutions have revealed the inappropriateness of theoretical approaches to employ a homogeneity (or mean-field) assumption, treating the tube radius as a constant, while experiments ,− and simulations indicate substantial heterogeneities. The common outcome of these studies indicates that both the concentration-dependent distributions of the tube radius P ( R e ) and of the entanglement length P ( L e ) are nonsymmetric Gaussian functions.…”