Investigation on Induced Non-Tilted Smectic A* and Thermochromic Effect in Tilted Smectic C* Phase of Linear Double Hydrogen Bonded Ferroelectric Liquid Crystals

摘要

Linear double hydrogen bonded ferroelectric liquid crystal (HBFLC) complexes are derived from non-mesogenic (R)-(+)-methylsuccinic acid and mesogenic 4-n-alkyloxybenzoic acids. Fourier transform infrared (FT-IR), polarizing optical microscope (POM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) studies are used to verify the existence of intermolecular hydrogen bonds in the synthesized HBFLC complexes. An induced orthogonal non-tilted smectic A* phase and a noteworthy observation of a thermally tuned thermochromic phenomenon are analyzed by using textural and thermal studies. Due to increasing elastic viscous force, the induced hexagonal higher- order smectic G* phase is reported in the lower alkyloxy carbon mesogens whereas the same is not observed in the individual compounds. Based on the temperature and change in the alkyloxy chain length, the induced thermochromic effect is discussed. Quenching of the nematic phase by an induced orthogonal phase is observed. Other liquid crystal parameters, such as the melting point, the phase transition temperature, the texture and the enthalpy, are reported.