Introduction to the Molecular Theory of Nematic Liquid Crystals

  • Peter J. Wojtowicz


In this chapter we consider the very simplest approach to the molecular theory of liquid crystals. We shall approach the theory phenomenologically, treating the problem of the existence of the nematic phase as an order-disorder phenomenon. Using the observed symmetry of the nematic phase we shall identify an order parameter and then attempt to find an expression for the orientational potential energy of a molecule in the nematic liquid in terms of this order parameter. Such an expression is easily found in the mean field approximation. Once this is accomplished, expressions for the orientational molecular distribution function are derived and the thermodynamic functions simply calculated. The character of the transformation from nematic liquid crystal to isotropic fluid is then revealed by the theory, and the nature of the fluctuations near the transition temperature can be explored.


Nematic Liquid Crystal Nematic Phase Molecular Theory Isotropic Liquid Orientational Distribution Function 
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  1. 1.
    W. Maier and A. Saupe, Z. Naturforschg., Vol. 14a, p. 882 (1959) and Vol. 15a, p. 287 (1960).ADSGoogle Scholar
  2. 2.
    P. J. Wojtowicz, “Generalized Mean Field Theory of Nematic Liquid Crystals,” Chapter 4.Google Scholar
  3. 3.
    R. Williams, “Optical-Rotary Power and Linear Electro-Optic Effect in Nematic Liquid Crystals of p-Azoxyanisole,” J. Chem. Phys., Vol. 50, p. 1324 (1969)ADSCrossRefGoogle Scholar
  4. D. Meyerhofer, A. Sussman, and R. Williams, “Electro-Optic and Hydrodynamic Properties of Nematic Liquid Films with Free Surfaces,” J. Appl. Phys., Vol. 43, p. 3685 (1972).ADSCrossRefGoogle Scholar
  5. 4.
    J. S. Smart, Effective Field Theories of Magnetism, W. B. Saunders Co., Philadelphia, Pa. (1966).Google Scholar
  6. 5.
    E. R. Callen and H. B. Callen, “Anisotropic Magnetization,” J. Phys. Chem. Solids, Vol. 16, p. 310 (1960).ADSCrossRefGoogle Scholar
  7. 6.
    S. Chandrasekhar and N. V. Madhusudana, “Molecular Statical Theory of Nematic Liquid Crystals,” Acta Cryst., Vol. A27, p. 303 (1971).Google Scholar
  8. 7.
    R. L. Humphries, P. G. James, and G. R. Luckhurst, J. Chem. Soc., Faraday Trans. II, Vol. 68, p. 1031 (1972).CrossRefGoogle Scholar
  9. 8.
    G. H. Brown, J. W. Doane and D. D. Neff, A Review of the Structure and Physical Properties of Liquid Crystals, p. 43, CRC Press, Cleveland, Ohio (1971).Google Scholar
  10. 9.
    T. W. Stinson and J. D. Litster, “Pretransitional Phenomena in the Isotropic Phase of a Nematic Liquid Crystal,” Phys. Rev. Lett., Vol. 25, p. 503 (1970).ADSCrossRefGoogle Scholar
  11. 10.
    H. E. Stanley, Introduction to Phase Transitions and Critical Phenomena, Oxford University Press, N.Y., N.Y. (1971).Google Scholar
  12. 11.
    L. D. Landau and E. M. Lifshitz, Statistical Physics, p. 344, Pergamon Press Ltd., London (1958).MATHGoogle Scholar

Copyright information

© RCA Laboratories 1975

Authors and Affiliations

  • Peter J. Wojtowicz
    • 1
  1. 1.RCA LaboratoriesPrincetonUSA

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