Eur. Phys. J. E 4, 293-297
Simple Landau model of the smectic-A-isotropic phase transition
P.K. Mukherjee1, 2, H. Pleiner3 and H.R. Brand11 Theoretische Physik III, Universität Bayreuth, D-95540 Bayreuth, Germany
2 Department of Physics, Haldia Govt. College, P.O.-Debhog, Dist.-Midnapur, Pin-721657, India
3 Max-Planck-Institut für Polymerforschung, 55021 Mainz, Germany
brand@uni-bayreuth.de
(Received 27 June 2000)
Abstract
A simple Landau-type free energy function is presented to describe
the smectic-A-isotropic phase transition. Varying the
coupling between orientational and positional order parameters,
a smectic-A-isotropic or a nematic-isotropic phase
transition occurs. Within this model
the smectic-A-isotropic phase transition
is found to be always more strongly first order than
the nematic-isotropic phase transition. The theoretical results
are found to be in good agreement with all published experimental
results.
64.70.Md - Transitions in liquid crystals.
05.70.Fh - Phase transitions: general studies.
61.30.-v - Liquid crystals.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2001