Synthesis and Mesophase Behavior of Schiff Base Liquid Crystals with Long-chain Aliphatic-acid

5th Annual International Workshop on Materials Science and Engineering

Peng, Weinan^1 ; Li, Tianhe^1 ; Yao, Danshu^1

Department of Chemistry, Northeastern University, Shenyang

110004, China^1

关键词: Crystallization temperature;    Long-chain aliphatic acid;    Melting transitions;    Mesomorphic phasis;    Mesophase behavior;    p-Hydroxybenzaldehyde;    Polarizing optical microscopy;    Schlieren textures;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/585/1/012033/pdf
DOI  :  10.1088/1757-899X/585/1/012033

来源: IOP

【 摘 要 】

Utilizing p-chloroaniline, p-hydroxybenzaldehyde and aliphatic diacids with different chain length as raw materials, the Schiff base liquid crystals Cl-SBPA4, Cl-SBPA6, Cl-SBPA8 and Cl-SBPA10 were synthesized by condensation and esterification. Their chemical structures were confirmed by FTIR and 1H NMR spectra. The mesophase behaviors were studied by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). The influence of molecular structure on mesophase behavior and optical property were discussed. The results demonstrated that Cl-SBPA4 exhibited smectic mosaic texture, Cl-SBPA6 and Cl-SBPA8 showed nematic droplet and schlieren texture, while Cl-SBPA10 had no mesomorphic phases. With the increase of the length of flexible chain, their melting transition (Tm) and crystallization temperature (Tc) exhibited a trend of decreasing first and then going up.