低临界转换频率的双频驱动液晶分子的设计、制备及性能

he disadvantages of commercial dual frequency liquid crystals (DFLC), such as high crossover frequency, high driving voltage and less species, limit their application in display and electro-optical devices. According to the relationship between property and molecular structure, nine kinds of DFLC molecules were designed and prepared by variation in terminal chain, rigid core, position and number of lateral fluorine substitution. The molecular structures of these compounds were characterized by Fourier transform-infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (NMR). The phase transition temperature and phase types were investigated by differential scanning calorimetry (DSC) and polarizing optical microscope (POM). And dielectric constant and crossover frequency were measured by impedance analyzer. The pure molecular crossover frequency can be reduced to 20.1 thousand Hertz. Moreover, the molecular structures of all the compounds were studied by using the theory of density functional theory (DFT), and theoretical analysis consists with experimental results.