Poiseuille flow of discotic nematic liquid crystals’ onion textures

Abstract

The Poiseuille capillary flow of discotic nematic liquid crystals (DNLCs) is analyzed using the Ericksen–Leslie theory, for three families of static patterns known as escaped and defect core onion textures, defined by the orientation at the capillary’ centerline. The escaped textures have low-elastic energy and high dissipation cores. The defect core texture has a high elastic energy-low dissipation core. The Poiseuille flow of these textures exhibits non-parabolic velocity profiles and their apparent viscosities display shear thickening, with exponents close to 1/5±0.07. Up to an Ericksen number of a thousand, core conditions have a strong effect on the non-Newtonian rheology of discotic nematics displaying the onion texture.