Smectic-C tilt under shear in smectic-A elastomers.
Smectic-C tilt under shear in smectic-A elastomers.
复制标题
近晶-A 弹性体中剪切下的近晶-C 倾斜。
DOI：
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发表时间：
2008
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影响因子：
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通讯作者：
M. Warner
中科院分区：
文献类型：
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作者：
O. Stenull;T. Lubensky;J. Adams;M. Warner
Stenull and Lubensky[Phys.Rev.E.76,011706(2007年)]认为，近晶弹性体中，指向矢相对于法线的剪切应变和倾斜是耦合的，其中一种的施加必然导致另一种的发展。这尤其意味着，近晶-A弹性体在简单剪切下将产生近晶-C类指向矢的倾斜。最近，克莱默和芬克尔曼[e-print arxiv：0708.2024；Phys.Rev.E78,021704(2008年)]，使用两种不同的剪切几何形状对近晶-A弹性体进行了剪切实验。其中一个实验实现了简单剪切，为近晶C类倾斜的发展提供了明确的证据。在这里，我们推广了亚当斯和华纳提出的近晶弹性体模型。Rev.E71,021708(2005年)]，并用它来研究Kramer和Finkelmann所研究的两个几何形状在剪切下的SMC样倾斜的大小。利用模型参数的合理估计，我们估计了两种几何形状的倾角，并将我们的估计与实验结果进行了比较。另一种剪切几何是有问题的，因为它在片状样品中引入了额外的面内压缩，从而导致了我们讨论的不稳定性。
Stenull and Lubensky [Phys. Rev. E 76, 011706 (2007)] have argued that shear strain and tilt of the director relative to the layer normal are coupled in smectic elastomers and that the imposition of one necessarily leads to the development of the other. This means, in particular, that a smectic-A elastomer subjected to a simple shear will develop smectic-C-like tilt of the director. Recently, Kramer and Finkelmann [e-print arXiv:0708.2024; Phys. Rev. E 78, 021704 (2008)], performed shear experiments on smectic-A elastomers using two different shear geometries. One of the experiments, which implements simple shear, produces clear evidence for the development of smectic-C-like tilt. Here, we generalize a model for smectic elastomers introduced by Adams and Warner [Phys. Rev. E 71, 021708 (2005)] and use it to study the magnitude of SmC-like tilt under shear for the two geometries investigated by Kramer and Finkelmann. Using reasonable estimates of model parameters, we estimate the tilt angle for both geometries, and we compare our estimates to the experimental results. The other shear geometry is problematic since it introduces additional in-plane compressions in a sheetlike sample, thus inducing instabilities that we discuss.