Pretransitional fluctuations in the isotropic phase of a lyotropic chromonic liquid crystal
Pretransitional fluctuations in the isotropic phase of a lyotropic chromonic liquid crystal
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DOI：
10.1103/physreve.70.051706
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发表时间：
2004-11-01
影响因子：
2.4
通讯作者：
Anisimov, MA
中科院分区：
文献类型：
--
作者：
Nastishin, YA;Liu, H;Anisimov, MA
我们已经研究了各向同性的色甘酸二钠（cromoglycate）的水溶液中的pretransitional波动的静态和动态光散射。Croydrin是溶致发色液晶的代表，其结构单元是由盘状分子聚集体形成的细长棒。通过结合光散射和粘度测量，我们已经确定了相关长度和弛豫时间的取向序参数波动和估计的cropharyn聚集体的大小。光散射的相变前行为并不完全遵循经典的Landau-de Gennes模型。这一特征很可能与crophyn聚集体的可变长度有关。我们已经观察到了一个戏剧性的增加的剪切粘度附近的过渡到α相，这一事实与增长的超分子聚集体的想法。陡峭的温度依赖性的粘度是伴随着一个几乎与温度无关的平移扩散系数。
We have studied isotropic-to-nematic pretransitional fluctuations in an aqueous solution of disodium cromoglycate (cromolyn) by static and dynamic light scattering. Cromolyn is a representative of lyotropic chromonic liquid crystals with building units being elongated rods formed by aggregates of disk-like molecules. By combining light-scattering and viscosity measurements we have determined the correlation length and relaxation time of the orientational order-parameter fluctuations and estimated the size of the cromolyn aggregates. The pretransitional behavior of light scattering does not completely follow the classic Landau-de Gennes model. This feature is most probably associated with the variable length of cromolyn aggregates. We have observed a dramatic increase of the shear viscosity near the transition to the nematic phase, the fact which correlates with the idea of growing supramolecular aggregates. The steep temperature dependence of the viscosity is accompanied by a practically temperature-independent translational diffusion coefficient.