Stelzer J, Bernhard R
Schwetzinger Strasse 20, 69190 Walldorf (Baden), Germany.
Phys Rev E Stat Nonlin Soft Matter Phys. 2001 Feb;63(2 Pt 1):021510. doi: 10.1103/PhysRevE.63.021510. Epub 2001 Jan 26.
Surface-induced profiles of both nematic and smectic order parameters in a nematic liquid crystal, ranging from an orienting substrate to "infinity," were evaluated numerically on the basis of an extended Landau theory. In order to obtain a smooth behavior of the solutions at "infinity," a boundary energy functional was derived by linearizing the Landau energy around its equilibrium solutions. We find that the intrinsic wave number of the smectic structure, which plays the role of a coupling between nematic and smectic order, strongly influences the director reorientation. Whereas the smectic order is rapidly decaying when moving away from the surface, the uniaxial nematic order parameter shows an oscillatory behavior close to the substrate, accompanied by a nonzero local biaxiality.
基于扩展的朗道理论,对向列型液晶中从取向衬底到“无穷远”的向列序参数和近晶序参数的表面诱导分布进行了数值评估。为了在“无穷远”处获得解的平滑行为,通过在其平衡解周围对朗道能量进行线性化,导出了边界能量泛函。我们发现,近晶结构的本征波数在向列序和近晶序之间起耦合作用,强烈影响指向矢的重新取向。当远离表面时,近晶序迅速衰减,而单轴向列序参数在靠近衬底处表现出振荡行为,并伴有非零的局部双轴性。