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Bifurcation analysis of the twist-Fréedericksz transition in a nematic liquid-crystal cell with pre-twist boundary conditions

Published online by Cambridge University Press:  01 June 2009

FERNANDO P. DA COSTA
Affiliation:
Departamento de Ciências e Tecnologia, Universidade Aberta, Rua Fernão Lopes, 9, 2° Dto., P-1000-132 Lisboa, Portugal, and Centro de Análise Matemática, Geometria e Sistemas Dinâmicos, Instituto Superior Técnico, TU Lisbon, Av. Rovisco Pais, 1, P-1049-001 Lisboa, Portugal email: fcosta@univ-ab.pt
EUGENE C. GARTLAND JR.
Affiliation:
Department of Mathematical Sciences, Kent State University, P.O. Box 5190, Kent, OH 44242-0001, USA email: gartland@math.kent.edu
MICHAEL GRINFELD
Affiliation:
Department of Mathematics, University of Strathclyde, 26 Richmond Street, Glasgow G1 1XH, UK email: caas05@maths.strath.ac.uk
JOÃO T. PINTO
Affiliation:
Department of Mathematics and Centro de Análise Matemática, Geometria e Sistemas Dinâmicos, Instituto Superior Técnico, TU Lisbon, Av. Rovisco Pais, 1, P-1049-001 Lisboa, Portugal email: jpinto@math.ist.utl.pt

Abstract

Motivated by a recent investigation of Millar and McKay [Director orientation of a twisted nematic under the influence of an in-plane magnetic field. Mol. Cryst. Liq. Cryst435, 277/[937]–286/[946] (2005)], we study the magnetic field twist-Fréedericksz transition for a nematic liquid crystal of positive diamagnetic anisotropy with strong anchoring and pre-twist boundary conditions. Despite the pre-twist, the system still possesses ℤ2 symmetry and a symmetry-breaking pitchfork bifurcation, which occurs at a critical magnetic-field strength that, as we prove, is above the threshold for the classical twist-Fréedericksz transition (which has no pre-twist). It was observed numerically by Millar and McKay that this instability occurs precisely at the point at which the ground-state solution loses its monotonicity (with respect to the position coordinate across the cell gap). We explain this surprising observation using a rigorous phase-space analysis.

Type
Papers
Copyright
Copyright © Cambridge University Press 2009

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References

[1]Abramowitz, M. & Stegun, I. A. (editors) (1972) Handbook of Mathematical Functions, Dover, New York.Google Scholar
[2]Chandrasekhar, S. (1992) Liquid Crystals, 2nd ed., Cambridge University Press, Cambridge.CrossRefGoogle Scholar
[3]da Costa, F. P., Grinfeld, M., Mottram, N. J. & Pinto, J. T. (2007) Uniqueness in the Freedericksz transition with weak anchoring (to appear in J. Differ. Equ.).Google Scholar
[4]Fiedler, B. & Rocha, C. (1996) Heteroclinic orbits of semilinear parabolic equations. J. Differ. Equ. 125, 239281.CrossRefGoogle Scholar
[5]de Gennes, P. G. & Prost, J. (1993) The Physics of Liquid Crystals, 2nd ed., Clarendon Press, Oxford.CrossRefGoogle Scholar
[6]Krasnoselskii, M. (1964) Topological Methods in the Theory of Nonlinear Integral Equations, MacMillan, New York.Google Scholar
[7]Krein, M. & Rutman, M. (1962) Linear operators leaving invariant a cone in banach space (Engl. Transl.). Am. Math. Soc. Transl., Ser. 1, 10, 199325.Google Scholar
[8]Millar, H. (2007) Mathematical Modelling of Nematic and Smectic Liquid Crystals, PhD thesis, University of Strathclyde, Glasgow.Google Scholar
[9]Millar, H. & McKay, G. (2005) Director orientation of a twisted nematic under the influence of an in-plane magnetic field. Mol. Cryst. Liq. Cryst. 435, 277/[937]–286/[946].CrossRefGoogle Scholar
[10]Schaaf, R. (1990) Global Solution Branches of Two Point Boundary Value Problems, Lecture Notes in Mathematics, Vol. 1458. Springer–Verlag, Berlin.CrossRefGoogle Scholar
[11]Smoller, J. & Wasserman, A. (1981) Global bifurcation of steady-state solutions. J. Differ. Equ. 39, 269290.CrossRefGoogle Scholar
[12]Stewart, I. W. (2004) The Static and Dynamic Continuum Theory of Liquid Crystals. The Liquid Crystals Book Series, Vol. 2, Taylor & Francis, London.Google Scholar
[13]Virga, E. G. (1994) Variational Theories for Liquid Crystals. Applied Mathematics and Mathe-matical Computation, Vol. 8, Chapman & Hall, London.Google Scholar