Fluorination Enables Dual Ferroelectricity in Both Solid- and Liquid-Crystal Phases

Area of Science:

• Materials Science
• Condensed Matter Physics
• Crystallography

Background:

• Ferroelectric materials exhibit spontaneous electric polarization.
• Achieving ferroelectricity in both solid crystal (SC) and liquid crystal (LC) phases of a single material is challenging.
• The ferroelectricity of cholesteric liquid crystals (CLCs) remains largely unexplored.

Purpose of the Study:

• To design and synthesize a material exhibiting ferroelectricity in both solid crystal and cholesteric liquid crystal phases.
• To investigate the effect of fluorination on the ferroelectric properties of dihydrocholesteryl benzoate derivatives.
• To explore the potential of designing dual ferroelectric materials.

Main Methods:

• Chemical synthesis involving H/F substitution on dihydrocholesteryl benzoate.
• Characterization of material properties using polarization-voltage hysteresis loops.
• Analysis of crystal structure and phase transitions, including space group determination.

Main Results:

• Successfully designed ferroelectric dihydrocholesteryl 4-fluorobenzoate (4-F-BDC).
• 4-F-BDC exhibits ferroelectricity in both its solid crystal and cholesteric liquid crystal phases.
• Fluorination induced a polar P1 space group and a new solid-to-solid phase transition.
• Well-shaped polarization-voltage hysteresis loops confirmed clear ferroelectricity.

Conclusions:

• Demonstrated dual ferroelectricity in a single material across solid crystal and cholesteric liquid crystal phases.
• Established fluorination as an effective strategy for designing dual ferroelectric materials.
• Opened new possibilities for exploring the interplay between ferroelectric solid and liquid crystal phases.