Influences of surface and flexoelectric polarization on the effective anchoring energy in nematic liquid crystal  

作　　者：关荣华 叶文江 邢红玉 

机构地区：[1]School of Sciences,North China Electric Power University [2]School of Sciences,Hebei University of Technology

出　　处：《Chinese Physics B》2015年第10期349-358,共10页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(Grant Nos.11274088,11374087,and11304074);the Natural Science Foundation of Hebei Province,China(Grant No.A2014202123);the Research Project of Hebei Provincial Education Department,China(Grant No.QN2014130);the Key Subject Construction Project of Hebei Provincial University,China

摘　　要：The physical effects on surface and flexoelectric polarization in a weak anchoring nematic liquid crystal cell are investigated systematically. We derive the analytic expressions of two effective anchoring energies for lower and upper substrates respectively as well as their effective anchoring strengths and corresponding tilt angles of effective easy direction.All of these quantities are relevant to the magnitudes of both two polarizations and the applied voltage U. Based on these expressions, the variations of effective anchoring strength and the tilt angle with the applied voltage are calculated for the fixed values of two polarizations. For an original weak anchoring hybrid aligned nematic cell, it may be equivalent to a planar cell for a small value of U and has a threshold voltage. The variation of reduced threshold voltage with reduced surface polarization strength is also calculated. The role of surface polarization is important without the adsorptive ions considered.The physical effects on surface and flexoelectric polarization in a weak anchoring nematic liquid crystal cell are investigated systematically. We derive the analytic expressions of two effective anchoring energies for lower and upper substrates respectively as well as their effective anchoring strengths and corresponding tilt angles of effective easy direction.All of these quantities are relevant to the magnitudes of both two polarizations and the applied voltage U. Based on these expressions, the variations of effective anchoring strength and the tilt angle with the applied voltage are calculated for the fixed values of two polarizations. For an original weak anchoring hybrid aligned nematic cell, it may be equivalent to a planar cell for a small value of U and has a threshold voltage. The variation of reduced threshold voltage with reduced surface polarization strength is also calculated. The role of surface polarization is important without the adsorptive ions considered.

关 键 词：surface and flexoelectric polarization effective anchoring energy easy direction hybrid aligned nematic threshold voltage 

分 类 号：O753.2[理学—晶体学] TQ053.5[化学工程]