Design, synthesis and characterization of calamitic shaped optical active azo LCs: Structure property relationship

Abstract

Pyridine-based two homologues series containing a naphthyl ring have been synthesized and characterized using analytical and spectroscopic techniques. The liquid crystalline behavior of these azo-ester materials was studied by polarizing optical microscopy and further studied by differential scanning calorimetry analysis. In this study, we have studied the effect of lateral substituent on mesomorphic properties. The synthesized materials from both series exhibited a smectic C and nematic type mesophase. Azo-linked mesogens exhibited good thermal stability with a broad transition temperature range of mesophase. Furthermore, the structure–property relationship was studied for more understanding about the exhibition of mesogenic properties.

Graphical Abstract

Keywords:

• Azo dye
• enantiotropic
• liquid crystal
• optical active
• thermotropic

Acknowledgments

The authors acknowledge the Head of Department of Chemistry, School of Science, Gujarat University for providing lab facility and infrastructure to carry out this work. The authors also acknowledge IIT Mandi and IIT Indore for providing analytical and spectral services. Vinay S. Sharma gratefully acknowledges Human Resource Development Group-Council of Scientific & Industrial Research (CSIR), New Delhi for Research Associate Fellowship (File No.: 09/070(0075)2020 EMR-I). We thank Mr. Deepak Suthar (Department of Physics, Mohanlal Sukhadia University) for his fruitful discussion on high temperature XRD analysis.

Additional information

Funding

This work was supported by the Council of Scientific and Industrial Research, India.