Comprehensive Characterization of a Reference Ferroelectric Nematic Liquid Crystal Material.

Among the recently developed ferroelectric nematic liquid crystals, FNLC-919, synthesized by Merck Electronics KGaA, stands out for its stable, room-temperature, ferroelectric nematic (NF) phase. This renders it a promising candidate for both fundamental research and device-level applications. In this study, we present a comprehensive experimental investigation of FNLC-919, focusing on its structural, optical, dielectric, and elastic properties in the paraelectric nematic (N) and the intermediate antiferroelectric phase (dubbed NX) that occur in a temperature range between the N and NF phases. Key material parameters such as ferroelectric polarization, viscosity, and nanostructure are characterized as functions of temperature in all mesophases, while the orientational elastic constants are determined only in the N and NX phases. Our findings are compared with prior results concerning the benchmark compound DIO that also exhibits the phase sequence N-NX-NF and reveals a smectic-like mass density wave coinciding with antiferroelectric ordering in the NX phase.