Rheology of an inverted cholesteric droplet under shear flow

Abstract

The dynamics of a quasi two-dimensional isotropic droplet in a cholesteric liquid crystal medium under symmetric shear flow is studied by lattice Boltzmann simulations. We consider a geometry in which the flow direction is along the axis of the cholesteric, as this setup exhibits a significant viscoelastic response to external stress. We find that the dynamics depends upon the magnitude of the shear rate, the anchoring strength of the liquid crystal at the droplet interface and the chirality. While for low shear rate and weak interface anchoring the system shows a non-Newtonian behavior, a Newtonian-like response is observed at high shear rate and strong interface anchoring. This is investigated both by estimating the secondary flow profile, namely a flow emerging along the out-of-plane direction (absent in fully Newtonian fluids, such as water), and by monitoring defect formation and dynamics which alter significantly the rheological response of the system.

arXiv comment14 pages, 5 figures. Contribution for the special issue Liquid Crystal Rheology

References in corpus (6)

• Self-assembly of colloid-cholesteric composites provides a possible route to switchable optical materials
• Numerical calculations of the phase diagram of cubic blue phases in cholesteric liquid crystals
• Domain growth in cholesteric blue phases: hybrid lattice Boltzmann simulations
• Bistable defect structures in blue phase devices
• Self-Assembly and Nonlinear Dynamics of Dimeric Colloidal Rotors in Cholesterics
• Rheology of distorted nematic liquid crystals