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.
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.