Dependence of mesomorphism on terminal polar group in novel azoester series

Abstract

Novel homologous series 4-(4′-n-alkoxy benzoyloxy) napthyl azo 4″–bromo benzenes, consisted of 11 members of a series. All the 11 members (ethoxy to hexadecyloxy) except hexadecyloxy are only enantiotropically nematogenic without exhibition of any smectogenic character. Transition temperatures and the textures are determined by an optical polarizing microscopy equipped with a heating stage. Textures of a nematic phase are threaded or schlieren. Analytical and spectral data supported the molecular structure of homologs. Transition curves viz., solid-nematic and nematic-isotropic showing phase behavior of the mesophase in a phase diagram behave in normal manner. Alternation of transition temperatures is exhibited by N–I transition curve. Thus, novel series is entirely nematogenic and high ordered melting type. Thus, synthesis of a novel azoester homologous series is carried out with a view to understand and establish the effect of molecular structure on Liquid crystal (LC) behaviors of a substance.

Keywords:

• Liquid crystal
• mesogen
• mesomorphism
• nematic
• smectic

Acknowledgements

The authors are thankful to the Prof. and Head; Dr. V. K. Jain, Department of Chemistry, School of Sciences, Gujarat University, Ahmedabad for his valuable support and co-operation in research work.