Crystallization Kinetics in Liquid Crystals with Hexagonal Precursor Phases by Calorimetry

Padmaja, S and Ajit, Narayanan and Srinivasulu, M and Girish, S R and Pisipati, V G K M and Potukuchi, D M (2010) Crystallization Kinetics in Liquid Crystals with Hexagonal Precursor Phases by Calorimetry. Zeitschrift für Naturforschung , 65a. pp. 733-744. ISSN 0932–0784

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Abstract

Design and characterization of Schiff based liquid crystalline nO.m compounds exhibiting hexagonal smectic phases are reported. Crystallization kinetics investigations are carried out in the liquid crystals (LCs) exhibiting hexagonal ordered orthogonal and tilted precursor LC phases by calorimetry. The Avrami theory is referred and results are analyzed. Influence of molecular ordering, structure, and dimensionality of the LC precursor phase on kinetics is studied. Effect of shape and lexibility of the molecule for nucleation and growth processes is investigated. Varying rate of kinetics reflects upon the transit of the system from constant type to independent type of nucleation. The trends in the Avrami parameter b and exponent n suggest sporadic nucleation. Crystal growth is interpreted as heterogeneous permeation of layered domains (or aggregates) formed by needle shaped calamitic molecules. Calorimetric observations at different crystallization temperatures CT and hold time t infer diffusion mediated crystallization.

Item Type: Article
Additional Information: Verlag der Zeitschrift fu¨r Naturforschung
Uncontrolled Keywords: Crystallisation; Kinetics; Hexagonal LC Phases; Precursor; Nucleation; Growth; Diffussion
Subjects: Engineering > MIT Manipal > Chemistry
Depositing User: MIT Library
Date Deposited: 09 Feb 2013 07:49
Last Modified: 09 Feb 2013 07:49
URI: http://eprints.manipal.edu/id/eprint/78324

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