Bailey C, Gartland E C, Jákli A
Chemical Physics Interdisciplinary Program and Liquid Crystal Institute, Kent State University, Kent, Ohio 44242, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2007 Mar;75(3 Pt 1):031701. doi: 10.1103/PhysRevE.75.031701. Epub 2007 Mar 5.
Recently it was found that fluid smectic phases of bent core liquid crystals formed freestanding fibers of extremely high slenderness ratios. Studies of these fibers showed that their structure was composed of concentric cylindrical smectic layers. For this configuration to be stable there must be an energy term that desires bending of the smectic layers. We show that an energy term that deals with the divergence of the dipolar direction can encourage layer bending if the layer chirality value is allowed to vary. The energy term associated with holding the layer chirality is closely related to layer compressions and electrical self-interactions. For our model, we assumed a simple smectic-C geometry with constant molecular tilt and cone angle defined by the director with respect to the layer normal, but allowed a constant variation of the polar direction about the director. Applying this simplified model to a free energy which accounts for director distortions, divergence of the polar direction, biaxial layer strain, surface tension, and electrical self-interactions, we were able to show consistency between the stable fiber radius and other properties predicted in our model to results from experimental studies.
最近发现，弯曲核液晶的流体近晶相形成了具有极高长径比的独立纤维。对这些纤维的研究表明，它们的结构由同心圆柱状近晶层组成。为使这种构型稳定，必须存在一个促使近晶层弯曲的能量项。我们表明，如果允许层手性值变化，一个处理偶极方向散度的能量项可以促进层弯曲。与保持层手性相关的能量项与层压缩和电自相互作用密切相关。对于我们的模型，我们假设了一个简单的近晶 - C几何结构，分子倾斜度和由指向矢相对于层法线定义的锥角恒定，但允许极方向围绕指向矢有恒定变化。将这个简化模型应用于一个自由能，该自由能考虑了指向矢畸变、极方向散度、双轴层应变、表面张力和电自相互作用，我们能够证明我们模型中预测的稳定纤维半径和其他性质与实验研究结果之间的一致性。
