Atomistic Mechanism of the Spontaneous Formation of Ferroelectric Nematic Order from an Isotropic Liquid
Year: 2026
Type: preprint
Abstract: Ferroelectric nematic (N F ) liquid crystals have fluidity with macroscopic polar order, yet the transition pathway at the molecular scale by which an isotropic liquid spontaneously develops long-range ferroelectric order remains poorly understood. Here, we demonstrated that microsecond-scale, unbiased all-atom molecular dynamics simulations can reproduce the spontaneous development of strong, system-wide polar order from an initially isotropic state. For DIO, highly polar local domains emerged upon cooling but remained nanoscopic because slow molecular diffusion kinetically suppressed their further growth. In contrast, UUZU-2N, which exhibits an enantiotropic N F phase at relatively high temperatures, underwent progressive polardomain growth and coalescence, ultimately reaching a nearly monodomain state with a polar order parameter of 𝑃 1 ≈ 0.9. The calculated spontaneous polarization reached 6.7 μC/cm 2 , in reasonable agreement with experiment. Notably, nematic orientational order developed rapidly, whereas long-range polar order emerged over several microseconds through much slower domain coarsening. The spontaneous development of strong polar order was also reproduced for C2-BOE. Further structural analyses revealed characteristic offset configurations and head-to-tail correlations between neighboring molecules. In comparison with molecular electrostatic distributions, it is suggested that longitudinally asymmetric and modulated charge distributions contribute to the stabilization of these polar arrangements. These results provide an atomistic mechanism connecting molecular electrostatics, local packing, domain coarsening, and macroscopic polarization in the N F liquid crystals.
Source: ChemRxiv
Language: English
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7204885824