Systematic Fluorination Is a Powerful Design Strategy toward Fluid Molecular Ferroelectrics

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 24, 2025

Ferroelectric nematic (NF) liquid crystals combine liquid-like fluidity and orientational order of conventional nematics with macroscopic electric polarization comparable in magnitude to solid-state ferroelectric materials. Here, we present a systematic study twenty-seven homologous materials various fluorination patterns, giving new insight into the molecular origins spontaneous polar ordering fluid nematics. Beyond our initial expectations, find highest stability NF phase be specific patterns rather than maximal fluorination, which might expected based on simple models. We delicate balance between apolar nematics, is entirely dictated by substitution fluorine atoms. Aided electronic structure calculations, show this have its radial distribution charge across surface, molecules possessing more oscillatory electrons their surfaces higher propensity form phases. This work provides set ground rules design principles that can inform synthesis future nematogens.

Language: Английский

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Fluorination: Simple Change but Complex Impact on Ferroelectric Nematic and Smectic Liquid Crystal Phases

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 7, 2025

A series of liquid crystal (LC) materials are reported, which form a variety ferroelectric nematic and smectic phases. The relationship between the number position lateral fluorine substituents formation LC phases is investigated. While addition increases temperature at order appears, fluorination phase sequence more complicated. Introducing can either suppress or promote phases, depending on their within molecule, interplay these trends allows for exotic to appear.

Language: Английский

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Thermotropic reentrant isotropic symmetry and induced smectic antiferroelectricity in the ferroelectric nematic material RM734

Proceedings of the National Academy of Sciences, Journal Year: 2025, Volume and Issue: 122(16)

Published: April 18, 2025

We report a transition from the ferroelectric nematic liquid crystal (N F ) phase to lower-temperature, apolar fluid having reentrant isotropic symmetry (I R ), in compound RM734 doped with small concentrations of ionic liquids 1-Butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF 6 or 1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM-TFSI). Even trace amount dopant facilitates kinetic pathway for N I , enabling simple cooling produce this rather than resulting immediate crystallization. The was also obtained absence specific doping by appropriate temperature cycling three distinct, as-synthesized-and-purified batches RM734, two commercial and one our laboratory. Ionic stabilizes smectic Z A an additional birefringent antiferroelectric director parallel layers, significantly increasing its range between paraelectric phases BMIM concentration.

Language: Английский

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Spontaneous Twist of Ferroelectric Smectic Blocks in Polar Fluids

Advanced Materials, Journal Year: 2025, Volume and Issue: unknown

Published: March 24, 2025

In soft matter, the polar orientational order of molecules can facilitate coexistence structural chirality and ferroelectricity. The ferroelectric nematic (NF) state, exhibited by achiral calamitic with large dipole moments, serves as an ideal model for emergence spontaneous chirality. This chiral ground state arises from a left- or right-handed twist polarization due to depolarization effects. contrast, smectic characterized lamellar structure lower symmetry, experiences significantly higher energy associated layer-twisting deformations formation domain walls, thus avoiding continuously twisted layered structure. this study, two types (BOE-NO2 DIOLT) are reported that possess different molecular structures but exhibit NF-ferroelectric phase sequence. It is demonstrated NF inherited in phases BOE-NO2, which features larger moments steric hindrance moiety, thereby triggering blocks.

Language: Английский

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Reactive Fluid Ferroelectrics: A Gateway to the Next Generation of Ferroelectric Liquid Crystalline Polymer Networks

Small, Journal Year: 2025, Volume and Issue: unknown

Published: April 7, 2025

Abstract Herein it is reported the first examples of reactive mesogenic materials (RMs) which exhibit fluid ferroelectric order based on recently discovered nematic (N F ) phase. These N RMs and they provide steps toward next generation liquid crystalline polymer networks termed. The chemical synthesis characterization properties these reported, demonstrating that have lowest longitudinal molecular dipole moments (µ) any material 7.39 D. It go to demonstrate a potential use case this new class through stabilization matrix exhibits phase, increasing phase range from 75 120 °C. herein are an exciting step forward in crystal research, achievable, allowing for future development networks, elastomers polymers.

Language: Английский

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Spontaneous helix formation in a polar smectic phase

Materials Horizons, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

A new type of smectic phase, SmCHP, is presented, with a proper ferroelectric nature and spontaneously formed heliconical structure. Under the application an electric field, helix axis can be reoriented, without disturbing helical pitch.

Language: Английский

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