Synthesis, Characterization, and Dilatometric Studies on N-(p-n-Alkoxybenzylidene)-p-n-pentyloxyanilines Compounds

Abstract

Synthesis, textural characterization, differential scanning calorimetry, and dilatometry studies are carried out on a new homologous series of N-(p-n-alkoxy benzylidene)-p-n-pentyloxy anilines (nO.O5) where n = 1–18. The lower homologues of this series (n = 1–5) and a higher homologue (n = 16) exhibit monotropic Liquid Crystal (LC) phase. The other members of the series show enantiotropic LC phases, while 18O.O5 is a nonliquid crystal. The dilatometric studies on 7O.O5, 10O.O5, 13O.O5 and 16O.O5 reveal the first-order nature of Isotropic to Nematic Phase (IN), Isotropic to Smectic A Phase (IA), Nematic to Smectic C Phase (NC), Smectic A to Smectic B Phase (AB), Smectic C to Smectic B Phase (CB), and Smectic A to Krystal Phase (AK) transitions. The pretransition effects are estimated from dilatometry results. The results are compared with the available data on nO.m compounds.

Keywords:

• dilatometry
• liquid crystals
• pretransitional effects

ACKNOWLEDGMENT

The financial support of the Department of Science and Technology (Grant No. SP/S2/M-34/2000), New Delhi, India, is gratefully acknowledged.

Notes

N-Nematic; NB-Nematic, Smectic B; NABG-Nematic, Smectic A, Smectic B, Smectic G; NACFG-Nematic, Smectic A, Smectic C, Smectic F, Smectic G; NACBG-Nematic, Smectic A, Smectic C, Smectic B, Smectic G; ABG-Smectic A, Smectic B, Smectic G; AB-Smectic A, Smectic B; A-Smectic A; AF-Smectic A, Smectic F.

^a Peaks are not well resolved.

^a The thermal range of smectic A in these compounds is short, and hence the slope values are not reliable.

PW, Personal Work.

Note. The density jump is smaller compared to 7O.5 and 5O.7.