Study of anchoring characteristics and splay-bend elastic constant based on experiments with non-twisted nematic liquid crystal cells

• Autorzy: Kędzierski J. , Kojdecki M. A. , Raszewski Z. , Rutkowska J. , Piecek W. , Perkowski P. , Zieliński J. , Miszczyk E.
• Konferencja: Conference on Liquid Crystals : Chemistry, Physics and Applications ; (17 ; 09.2007 ; Augustów, Poland)
• Języki publikacji: EN

Abstrakty

EN

Possible influence of a nematics splay-bend elastic constant and corresponding free energy functional term on adequacy of description of nematics states is studied by comparing results of theoretical considerations and computer simulations with experimental data. Planar deformation states enforced in flat nematics cells by symmetric aligning cover coatings and external electric or magnetic fields are studied in one-dimensional approximation. Nematics material parameters and nematics-substrate coupling characteristics are determined from experimental data by immediate measurement or by solving inverse problems. Two series of cells with thicknesses between twenty and forty-four micrometers (in fact two wedge cells) with two different orienting substrates are investigated by measuring a cell optical response in a birefringence experimental system. Good agreement between optical retardation measured and simulated is observed. Posterior comparison of free energy contributions from substrate interactions and a hypothetical surface-like term leads to a conclusion that the last one together with a splay-bend elastic constant should be very small and can be neglected.

Słowa kluczowe

EN

nematics; nematics elastic constants; surface-like nematics elastic constants; nematics anchoring energy

• Wydawca: Stowarzyszenie Elektryków Polskich ; Polska Akademia Nauk ; Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego
• Czasopismo: Opto-Electronics Review
• Rocznik: 2008
• Tom: Vol. 16, No. 4
• Strony: 390--394
• Opis fizyczny: Bibliogr. 10 poz., wykr.

Twórcy

autor

Kędzierski J.

autor

Kojdecki M. A.

autor

Raszewski Z.

autor

Rutkowska J.

autor

Piecek W.

autor

Perkowski P.

autor

Zieliński J.

autor

Miszczyk E.

• Institute of Applied Physics, Military University of Technology, 00-908 Warsaw, Poland

Bibliografia

• 1. S. Stallinga S., J.A.M.M. van Haaren, and J.M.A. van den Eerenbeemd, “Influence of surface elasticity on the director profile of non-twisted nematic-liquid crystal cells”, Phys. Rev. E53, 1701-713 (1996).
• 2. S. Stallinga and G. Vertogen, “Solution of the Oldano-Barbero paradox”, Phys. Rev. E53, 1692-700 (1996).
• 3. V. M. Pergamenshchik, “Phenomenological approach to the problem of the K13 surface like elastic term in the free energy of a nematic liquid crystal”, Phys. Rev. E48, 1254-1264 (1993).
• 4. S. Faetti, “Theory of surfacelike elastic contributions in nematic liquid crystals”, Phys. Rev. E49, 4192-4205 (1994).
• 5. S. Faetti, “Resummation of higher-order terms in the free-energy density of nematic liquid crystals”, Phys. Rev. E49, 5332-5344 (1994).
• 6. J. Kędzierski, M.A. Kojdecki, Z. Raszewski, J. Zieliński, and E. Miszczyk, “Study of nematics-ubstrate coupling characteristics and nematics material parameters in dependence on cell thickness by using wedge cells of different cover coatings”, Mol. Cryst. Liq. Cryst. 450, 67-72 (2006).
• 7. J. Kędzierski, M. A. Kojdecki, Z. Raszewski, P. Perkowski, J. Rutkowska, W. Piecek, L. Lipińska, and E. Miszczyk, “Composite method for determination of liquid crystal material parameters”, Mol. Cryst. Liq. Cryst. A352, 77-84 (2000).
• 8. J. Borycki, M. Wilczek, J. Kędzierski, and M.A. Kojdecki, “Surface free energy of chosen polyimides and anchoring energy of 6CHBT on these surfaces”, Proc. SPIE, 5565, 354-358 (2004).
• 9. J. Żmija, S. J. Kłosowicz, J. Kędzierski, E. Nowinowski-Kruszelnicki, J. Zieliński, Z. Raszewski, A. Walczak and J. Parka, “Application of liquid crystals in optical processing of optical signals”, Opto-Electr. Rev. 5, 93-106 (1997).
• 10. J. Kędzierski, Z. Raszewski, M. A. Kojdecki, J. Zieliński, E. Miszczyk and L. Lipińska, “Optical method for determining anisotropy of diamagnetic susceptibility of nematics and polar anchoring energy coefficient of nematics-substrate systems by using a cell of varying thickness”, Opto-Electr. Rev. 12, 299-303 (2004).