DOI: 10.1140/epje/i2002-10062-8
Non-uniformities in polymer/liquid crystal mixtures
II. Nematic nucleation
A. Matsuyama1, R.M.L. Evans2 and M.E. Cates31 Department of Chemistry for Materials, Faculty of Engineering, Mie University, Tsu Mie 514-8507, Japan
2 Department of Physics and Astronomy, The University of Leeds, Leeds LS2 9JT, UK
3 Department of Physics and Astronomy, The University of Edinburgh, Edinburgh EH9 3JZ, UK
matuyama@chem.mie-u.ac.jp
(Received 9 August 2002 / Published online: 22 November 2002)
Abstract
We theoretically model the nucleation of nematic droplets during phase
ordering in mixtures of a flexible polymer and a low-molecular-weight
liquid crystal. By appealing to classical nucleation theory (CNT), we
calculate the energy barrier to nucleation and the size of a critical
nucleus. We study the
influence of a metastable intermediate phase on the nucleation of the
nematic. Below a triple point in the phase diagram, there are two
distinct mechanisms for the formation of a nematic nucleus: 1) direct
nucleation from the isotropic phase and 2) nucleation via a precursor
metastable isotropic phase. We calculate the crossover concentration
as a function of temperature, delineating the regions of the phase
diagram in which each mechanism prevails. In the latter case, the
presence of a hidden metastable isotropic-isotropic binodal may either
promote or delay the nucleation of a nematic phase.
61.30.-v - Liquid crystals.
61.30.St - Lyotropic phases.
64.90.+b - Other topics in equations of state, phase equilibria, and phase transitions.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2002