Nonlinear Model for the Isotropic/Smectic A Phase Transition

N.M. Abukhdeir and A.D. Rey (Canada)


liquid crystals smectic modeling simulation optimiza tion


We present both solution and coefficient determination methods for a Landau-de Gennes type phenomenolog ical phase transition model. A homogeneous-volume form of the model is analyzed and shown to be valid for the isotropic/smectic-A transition sequence. A method is presented for the direct linking to experi mental observations through coefficient determination in the form of a nonlinear programming problem. A minimization analysis is utilized to simplify the non linear model. A computationally efficient and de terministic phase diagram generation method is pre sented based upon the single-variable form of the model. Phenomenological coefficients and the result ing phase diagram for the liquid crystal 12CB (do decylcyanobiphenyl) are presented and compared to experimental data. The results show good agreement with experimental data, validating the coefficient de termination method. In addition to this the deter mined constants are applicable for use in the full het erogeneous form of the model. Extensions to the sim ulation of free-standing smectic films are discussed.

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