Theoretische Physik II, Physikalisches Institut, Universität Bayreuth, D-95440 Bayreuth, Germany.
Soft Matter. 2014 Mar 21;10(11):1758-66. doi: 10.1039/c3sm52650j.
Using Monte Carlo simulation, we study a fluid of two-dimensional hard rods inside a small circular cavity bounded by a hard wall, from the dilute regime to the high-density, layering regime. Both planar and homeotropic anchoring of the nematic director can be induced at the walls through a free-energy penalty. The circular geometry creates frustration in the nematic phase and a polar-symmetry configuration with a distorted director field plus two +1/2 disclinations is created. At higher densities, a quasi-uniform structure is observed with a (minimal) director distortion which is relaxed via the formation of orientational domain walls. This novel structure is not predicted by elasticity theory and is similar to the step-like structures observed in three-dimensional hybrid slit pores. We speculate that the formation of domain walls is a general mechanism to relax elastic stresses under the conditions of strong surface anchoring and severe spatial confinement.
我们通过蒙特卡罗模拟研究了一种由二维硬棒组成的流体，该流体位于一个由硬壁围成的小圆形腔体内，从稀相到高密度的分层相。通过自由能罚函数，可以在壁上诱导出向列型指向矢的平面和各向同性两种锚定。圆形几何形状在向列相中产生了挫折，形成了具有扭曲指向矢场和两个 +1/2 位错的极对称结构。在更高的密度下，观察到一种具有（最小）指向矢扭曲的准均匀结构，该结构通过形成取向畴壁来松弛。这种新结构不能用弹性理论来预测，与在三维混合狭缝孔中观察到的阶梯状结构相似。我们推测，畴壁的形成是在强表面锚定和严重空间限制条件下，一种用于松弛弹性应力的通用机制。
