Fig. 1: Mirror symmetry breaking in flowing nematic LCLC solutions.
From: Flow-induced periodic chiral structures in an achiral nematic liquid crystal
a Periodic stripe patterns emerge from uniformly aligned nematic LCLC solutions upon the onset of flow. b Schematics of the transition from a uniform planar alignment at rest to a periodic double-twist structure under flow. c Retardance map (upper panel), where the colour represents the optical retardance δ averaged across the gap thickness, and the black rods denote the orientation of the director averaged across the gap thickness and projected onto the xy-plane. Along the distance L indicated as a red line, the retardance varies periodically (lower panel). The low-retardance regions are denoted as regions I, the regions in between as regions II. The gap thickness is b = 14 μm. d Director orientation. φ is the azimuthal angle and θ is the polar angle. e Fluorescence confocal polarising microscopy image of the stripe pattern in the xy-plane imaged close to the bottom wall of the microfluidic cell (upper panel). The white arrow represents the polarisation of the probing beam. Along L, the normalised fluorescence intensity, I, measured close to the top wall (black line) is out of phase with that measured close to the bottom wall (blue line) (lower panel). f Schematic of the periodic double-twist configuration (upper panel) and the corresponding stripe pattern (lower panel). g Map of the normalised light intensity under crossed polariser and analyser, In (lower panel), determined from the simulated periodic double-twist director field (upper panel).
