Comprehensive characterization of ferroelectric nematic liquid crystal FNLC919 as a reference material

Among the recently developed ferroelectric nematic liquid crystals, FNLC-919, synthesized by Merck Electronics, stands out for its stable, room temperature, ferroelectric nematic (N_F) 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 N_x) that occurs in a temperature range between the N and N_F 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 N_X phases. Our findings are compared with prior results on the benchmark compound DIO that also exhibits the phase sequence N-N_x-N_F and reveals a smectic-like mass density wave coinciding with antiferroelectric ordering in the N_x phase.