Abstract
This article is concerned with the application of an electric field along the planar layers of a finite sample of ferroelectric smectic C* liquid crystal with strong smectic anchoring at the boundaries. It will be seen by use of continuum theory that above a certain critical field strength it is energetically favourable for the helix to unwind such that the c-director becomes aligned perpendicular to the applied field throughout the sample. This problem is similar to that of untwisting the helical structure of a cholesteric liquid crystal [1], [2]; the differences lie in the symmetry and polarization of the smectic C* phase. Comparison of this work with that detailed in [2] will show that these two factors lead to significant differences in the analysis. The effects of sample width on the minimum field strength required for this untwisting are also examined and an expression is gained for the critical field strength in a large sample. In addition, director reorientation due to a reversal of the applied field is discussed.
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References
de Gennes P G (1968) Calcul de la distorsion d'une structure cholesterique par un champ magnetique. Solid State Comm. 6:163–165
Kedney P J, Stewart I W (1994) The untwisting of a bounded sample of cholesteric liquid crystal. Continuum Mech. Thermodyn. 6:141–148
Oseen C W (1933) The theory of liquid crystals. Transac. Far. Soc. 29:883–899
de Gennes P G (1974) The Physics of Liquid Crystals. Oxford University Press
Meyer R B (1977) Ferroelectric liquid crystals; a review. Mol. Crys. Liquid Crys. 40:33–48
Leslie F M, Stewart I W, Nakagawa M (1991) A continuum theory for smectic C liquid crystals. Mol. Crys. Liquid Crys. 198:443–454
Meyer R B, Liebert L, Strzelecki L, Keller P (1975) Ferroelectric liquid crystals. J. Phys. - Lett. 36:69–71
Leslie F M, Stewart I W, Carlsson T, Nakagawa M (1991) Equivalent smectic C liquid crystal energies. Continuum Mech. Thermodyn. 3:237–250
Carlsson T, Stewart I W and Leslie F M (1992) An elastic energy for the ferroelectric chiral smectic C phase. J. Phys. A: Math. General 25:2371–2374
Carlsson T, Stewart I W, Leslie F M (1991) Theoretical studies of smectic C liquid crystals confined in a wedge, stability and Frederiks transitions. Liquid Crys. 9:661–678
Abromowitz M A and Stegun I (1970) A Handbook of Mathematical Functions. U.S. Department of Commerce, N.B.S.
Gradshteyn I S, Ryzhik I M (1965) Tables of Integrals, Series and Products. Academic Press New York
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Kedney, P.J., Stewart, I.W. The electrical untwisting of a homeotropically aligned smectic C* liquid crystal. Continuum Mech. Thermodyn 7, 341–356 (1995). https://doi.org/10.1007/BF01176293
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DOI: https://doi.org/10.1007/BF01176293