Director Structures in a Chiral Nematic Slab: Threshold Field and Pitch Variations

Document Type : Regular Article


1 Department of Physics, Faculty of Science, Alzahra University, Tehran, Iran.

2 Department of Physics, Faculty of Science, Isfahan University, Isfahan, Iran.


Abstract The liquid crystal director distribution is determined for a confined chiral nematic slab. The molecular director distribution of the field-controlled chiral nematic slab is directly calculated. The director profiles for the tilt and the twist angles, under different applied fields, are calculated in the slab with weak boundary conditions. Then, the dependence of the threshold field on a dimensionless parameter containing the anchoring and thickness variations is obtained. The variation of the threshold field is found as a function of anchoring strengths for different ratios of the slab-thickness to the pitch, d/P. It confirms that for a constant ratio of d/P, the field decreasing rate in strong anchoring conditions is high and that by decreasing the strength of anchoring, the threshold field becomes approximately constant. This study is based on a stable and simple numerical method that gives accurate results in a short time, compared to the existing methods. The excellent agreement of the solutions with the previously reported solutions shows the usefulness of the method.

Graphical Abstract

Director Structures in a Chiral Nematic Slab: Threshold Field and Pitch Variations


[1] F.C. Frank, Discuss. Faraday Soc. 25 (1958) 19. W.H. De Jeu, Physical Properties of Liquid Crystalline Materials, Gordon and Breach Science Publishers, 1980.
[2] P.G. De Gennes, J. Prost, The Physics of Liquid Crystals, Oxford, New York, 1995.
[3] D. Demus, J. Goodby, G.W. Gray, H.W. Spiess, V.Vill, Physical Properties of Liquid Crystals, Wiley-VCH Verlag, Germany, 1999.
[4] I. Dierking, Textures of Liquid Crystals, Wiley-VCH Verlag, 2003.
[5] O.K. Dmitry, Phys. Rev. E 79 (2009) 030702/1.
[6] E. Kadivar, K. Rahimi, M.A. Shahzamanian, Liq.Cryst., 7 (2008) 815.
[7] S. Shoarinejad, M.A. Shahzamanian, J. Mol. Liq. 138 (2008) 14.
[8] G. Napoli, J. Phys. A: Math. Gen. 39 (2006) 11.
[9] R.H. Self, C.P. Please, T.J. Sluckin, Euro. J. Appl. Math. 13 (2002) 1.
[10] A.D. Kiselev, T.J. Sluckin, Phys. Rev. E 71 (2005) 031704/1.
[11] A. Rapini, Papoular, J. Phys. (Paris) Colloq. 30 (1969) C4.
[12] A. Sugimura, O.Y. Zhong, Phys. Rev. E 51 (1995) 784.
[13] Y. Guochen, Z. Shu-jing, H. Li-Jun, G. Rong-Hua, Liq. Cryst. 8 (2004) 1093.
[14] D. Krzyzanski, G. Derfel, Liq. Cryst. 951 (2002) 210.
[15] P. Ribiere, P. Oswald, J. Phys. (Paris) 51 (1990) 1703.
[16] I. Gvozdovskyy, O. Yaroshchuk, M. Serbina, Mol. Cryst. Liq. Cryst. 546 (2011) 202/1672.
[17] W.C. Yipa, H.S. Kwok, Appl. Phys. Lett. 4 (2001) 425.
[18] V.A. Belyakov, E.I. Kats, S.P. Palto, 1 (2004) 229. [19] W. Zhao, X.W. Chen, M. Iwamoto, Phys. Rev. 65 (2002) 031709/1.
[20] V.A. Belyakov, Mol. Cryst. Liq. Cryst. 489 (2008) 54/380.
Volume 1, Issue 2 - Serial Number 2
December 2013
Pages 134-141
  • Receive Date: 15 May 2013
  • Revise Date: 05 August 2013
  • Accept Date: 12 August 2013
  • First Publish Date: 01 December 2013