Room-temperature ferroelectric nematic liquid crystals: the influence of substituents on properties

Abstract

The discovery of ferroelectric nematic (N_F) liquid crystals represents a significant breakthrough in the field of soft matter physics. However, typical materials RM734 and DIO exhibit limited room-temperature applications because the temperature range of their N_F phases is relatively high. In this study, based on the room-temperature N_F liquid crystal monomer RT12155, the effects of substituents on the properties of N_F liquid crystal molecules were investigated by introducing different electron-withdrawing groups. The study confirms that a molecular dipole moment greater than 9 D is required to form the N_F phase, and the optimized structure has been verified to exhibit the N_F phase at room temperature. Additionally, the synergistic electron-withdrawing ability of –CN and –F is stronger than that of –NO₂, leading to higher polarization intensity in molecules containing –CN and –F. Furthermore, their dielectric responses differ between the isotropic phase and the N_F phase. This research offers important references for the molecular design, performance optimization, and practical application of room-temperature N_F liquid crystals in related fields.