Adams J M, Warner Mark, Stenull Olaf, Lubensky T C
Cavendish Laboratory, Cambridge, United Kingdom.
Phys Rev E Stat Nonlin Soft Matter Phys. 2008 Jul;78(1 Pt 1):011703. doi: 10.1103/PhysRevE.78.011703. Epub 2008 Jul 3.
Experimentally it is possible to manipulate the director in a (chiral) smectic- A elastomer using an electric field. This suggests that the director is not necessarily locked to the layer normal, as described in earlier papers that extended rubber elasticity theory to smectics. Here, we consider the case that the director is weakly anchored to the layer normal assuming that there is a free energy penalty associated with relative tilt between the two. We use a recently developed weak-anchoring generalization of rubber elastic approaches to smectic elastomers and study shearing in the plane of the layers, stretching in the plane of the layers, and compression and elongation parallel to the layer normal. We calculate, inter alia, the engineering stress and the tilt angle between director and layer normal as functions of the applied deformation. For the latter three deformations, our results predict the existence of an instability towards the development of shear accompanied by smectic- C-like order.
在实验中，利用电场可以在（手性）近晶A弹性体中操控指向矢。这表明指向矢不一定像早期将橡胶弹性理论扩展到近晶相的论文中所描述的那样锁定在层法线方向。在这里，我们考虑指向矢与层法线方向弱锚定的情况，假设两者之间的相对倾斜存在自由能惩罚。我们使用最近开发的将橡胶弹性方法推广到近晶弹性体的弱锚定理论，研究层平面内的剪切、层平面内的拉伸以及平行于层法线方向的压缩和伸长。我们特别计算了工程应力以及指向矢与层法线方向之间的倾斜角作为施加变形的函数。对于后三种变形，我们的结果预测存在一种向伴随近晶C类有序的剪切发展的不稳定性。
