Naphthylethyne based liquid crystals with high birefringence and characteristics of selective reflection

A series of high birefringence liquid crystalline molecules with cyano, isothiocyanato and trifluoromethyl terminal compounds based on naphthylethyne core was successfully synthesized and characterized. The molecular structures of the intermediates and resulting compounds were confirmed by Fourier transform infrared(FT-IR), nuclear magnetic resonance(NMR), mass spectrometry(MS), and elemental analysis(EA). Their thermal stability, transition temperatures, and phase sequences were investigated by simultaneous thermal analyzer polarized(STA), optical microscopy(POM) and differential scanning calorimetry(DSC). The birefringence was measured by using an Abbe refractometer. In addition, the selective reflection characteristics with naphthylethyne compounds were also studied.