Vanakaras Alexandros G, Samulski Edward T, Photinos Demetri J
Department of Materials Science, University of Patras, 26504 Patras, Greece.
Department of Chemistry and Applied Physical Sciences, University of North Carolina, Chapel Hill, NC 27599-3201, USA.
Soft Matter. 2025 Feb 12;21(7):1341-1352. doi: 10.1039/d4sm01229a.
Monte Carlo molecular simulations of curve-shaped rods show the propensity of such shapes to polymorphism revealing both smectic and polar nematic phases. The nematic exhibits a nanoscale modulated local structure characterized by a unique, polar, -symmetry axis that tightly spirals generating a mirror-symmetry-breaking organization of the achiral rods-form chirality. A comprehensive characterization of the polarity and its symmetries in the nematic phase confirms that the nanoscale modulation is distinct from the elastic deformations of a uniaxial nematic director in the twist-bend nematic phase. Instead it is shown that, analogous to the isotropic-to-nematic transition, entropy stabilizes the roto-translating polar director in the polar-twisted nematic phase. The conflation of macroscale form chirality in ferroelectric nematics with that in the twist-bend nematic stems from the misattribution of the nanoscale modulation in the lower temperature nematic "N phase" found in CB7CB dimers.
