Non-Newtonian rheology in twist-bend nematic liquid crystals

TL;DR

This paper introduces a qualitative model explaining the shear rheological behavior of twist-bend nematic liquid crystals, capturing shear-thinning, plateau, and Newtonian regimes, aligning well with recent experiments.

Contribution

A simple qualitative model describing shear rheology in twist-bend nematic liquid crystals, including critical shear rate estimates and rheological regime transitions.

Findings

Shear-thinning behavior at low shear rates

Plateau in stress at intermediate shear rates

Newtonian rheology at high shear rates

Abstract

In this work we present a simple qualitative model to describe shear rheological behavior of the twist-bend nematic liquid crystals. We find that at relatively low shear rate the effective viscosity decreases with the shear rate manifesting so-called shear-thinning phenomenon. At intermediate shear rate the stress is almost independent of the shear rate (a sort of plateau), and at large shear rate Newtonian rheology takes place. Within our theory we estimate the critical values of the shear rate in terms of coarse grained shear viscosity coefficients of the effective smectics equivalent to the twist-bend phase at large scales. The results of our work are in the agreement with recent experimental studies.