Crystallization Kinetics Study on Tilted Ordering in N-(p-n-Alkoxybenzylidene)-p-n-Alkylanilines (nO·m Compounds) by Thermal and Electrical Techniques Part II

Abstract

A systematic kinetic study of crystallization among two smectogens of higher homologues of the benzylideneaniline nO·m series viz 15O.8 and 15O.10 has been carried out by thermal microscopy, differential scanning calorimetry (DSC), and dielectric studies. The crystallization kinetics was studied by two techniques viz the traditional thermal analysis (DSC) and electrical studies viz capacitance and dielectric loss variation with temperature. The DSC thermograms were run from crystallization temperature to the isotropic melt for different time intervals. The liquid crystalline behavior together with the rate of crystallization of smectic ordering in newly synthesized nO·m compounds were discussed in relation to the kinetophase (which occurs prior to the crystallization). The molecular mechanism and dimensionality in the crystal growth were computed from the Avrami equation. The characteristic crystallization time (t*) at each crystallization temperature was deduced from the individual plots of log t and ΔH. Further, it was observed that the data obtained from DSC and dielectric studies were in good agreement with one another.

Keywords:

• crystallization kinetics
• dielectric study
• DSC
• nO·m compounds

ACKNOWLEDGMENTS

The authors thank the Management of Bannari Amman Institute of Technology for providing the laboratory and other infrastructural facilities. One of the authors (MLNMM), acknowledges the financial support provided by Department of Science and Technology, New Delhi, All India Council of Technical Education, New Delhi, and Defence Research Development Organization, New Delhi.