Non-affinity and fluid-coupled viscoelastic plateau for immersed fiber networks

TL;DR

This paper reveals a new dynamic response regime in fluid-immersed fiber networks, showing coupled fluid flow and network deformation with non-affine responses, leading to a unique viscoelastic plateau absent in vacuum conditions.

Contribution

It introduces a matrix-based solver to identify a novel fluid-coupled viscoelastic response regime in immersed fiber networks, highlighting the importance of hydrodynamic interactions.

Findings

Discovery of a fluid-coupled response regime with a viscoelastic plateau

Identification of non-affine deformation in both fluid and network components

Demonstration that hydrodynamic interactions alter mechanical response features

Abstract

We employ a matrix-based solver for the linear rheology of fluid-immersed disordered spring networks to reveal four distinct dynamic response regimes. One regime - completely absent in the known vacuum response - exhibits coupled fluid flow and network deformation, with both components responding non-affinely. This regime contains an additional plateau (peak) in the frequency-dependent storage (loss) modulus - features which vanish without full hydrodynamic interactions. The mechanical response of immersed networks such as biopolymers and hydrogels is thus richer than previously established, and offers additional modalities for design and control through fluid interactions.