N,N-Bis-(4-substituted phenyl)terephthalamides 의 액정성

Liquid Crystalline Properties of N,N-Bis-(4-substituted phenyl)terephthalamides

N,N-Bis-(4-substituted phenyl)terephthalamides were prepared and their thermal and liquid crystalline properties were studied by differential scanning calorimetry (DSC) and on a hot-stage of a polarizing microscope. The terminal substituent groups of the com pound were changed : X= -H, -F, -Cl, -Br, -I, -NO2 , -CN, -C6H5 , -CH3 , -C2H5 ,- OC2H5 , and -OC4H9 . The com pounds of X= -H, -F, -Cl, -Br, -I, -NO2 , -CH3, and-C2H5， were not liquid crystals. The com pound of X = -CN was monotropically nematic. The compounds of X= -C6H5 , - OC2H5 and - OC4H9 were enantiotropically smectic A. The group efficiency order of these com pounds was in the order of -C6H5 〉 - OC4H9 〉 -CN> -OC2H5.