溶液中向列型液晶有序度以及外场对它们的影响

ORDERS OF NEMATIC LIQUID CRYSTAL IN SOLUTION AND THE EFFECT OF EXTERNAL FIELDS ON THEM

根据Lebwohl-Lasher模型以及平均场近似得到了存在于外场中的溶液中向列型液晶分子有序度参数的自洽方程.无外场时,溶液中液晶发生一级相变,不同浓度相转变时<P_2>均为0.324,T^(N1)与浓度成正比,T_φ^(N1)=T_(φ=1)^(N1)φ。而存在外场时,液晶发生二级相变。

Self-consistent equation for order parameter of nematic liquid crystal (LC) in solution is obtained on the basis of Lebwohl-Lasher model and mean-field approximation. Numerical calculation shows that LC in solution with different volume fractions all undergo the first-order phase transition at <P2> =0.324 without external fields, and TN1is proportional to the volume fraction, TψN1 = TψN1=1ψ. Under applied external fields, LCs undergo second-order phase transition at < P2 > = 0.40. Distribution curves are in Ⅴ shape. The variation of the distribution mean square errors with> has a maximum at < P2 > = 0.20.