Shear rheology of amphiphilic cubic liquid crystals from large-scale kinetic lattice–Boltzmann simulations

Abstract

We investigate the rheological characteristics of ternary amphiphilic gyroid, diamond and primitive cubic phases under applied Couette flow simulated using a kinetic lattice–Boltzmann model and periodic Lees–Edwards boundary conditions. The simulated rheological response of the cubic phases is compared to experimental observations in lyotropic liquid crystals. We relate the variations in the non-Newtonian response and deformation under strain in these cubic phases to their triply bicontinuous cubic morphologies as well as to the differences in the interaction parameters between the three species present in the amphiphilic system. The large system sizes allow simulation of multiple domains which elucidate the correlation between the evolution of the defect texture and the change in the stress field of the cubic phase under applied Couette flow.