Parallel and perpendicular orientations observed in shear aligned SCA liquid crystal of main-chain polyester
Parallel and perpendicular orientations observed in shear aligned SCA liquid crystal of main-chain polyester
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DOI：
10.1021/ma0305232
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发表时间：
2004-03
期刊：
影响因子：
5.5
通讯作者：
M. Tokita;K. Tokunaga;S. Funaoka;K. Osada;J. Watanabe
中科院分区：
文献类型：
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作者：
M. Tokita;K. Tokunaga;S. Funaoka;K. Osada;J. Watanabe
使用锥板夹具检查主链BB-5（3-Me）聚酯的近晶CA（SCA）相的剪切排列行为。在近晶温度范围从100至140 °C，两个不同的取向已被确定由广角X射线衍射。在低于130 °C的温度下，近晶层以垂直于剪切方向且平行于速度梯度方向的单位法线排列（所谓的平行取向）。在各向同性化温度附近的高温下的剪切导致近晶层的取向，其单位法线垂直于流动和速度梯度方向（垂直取向）。在中间温度下，两种取向共存。用辐射沿着涡度方向测量的平行取向样品的SR-SAXS曲线包括在平行于链轴的速度梯度方向上具有约80 A间距的小峰。长间距大约是五倍以上的…
Shear alignment behavior was examined for smectic CA (SCA) phase of main-chain BB-5(3-Me) polyester using a cone-and-plate fixture. In the smectic temperature region from 100 to 140 °C, two distinct orientations have been identified by wide-angle X-ray diffraction. At temperatures lower than 130 °C, the smectic layers arrange with unit normal perpendicular to the shear direction and parallel to the velocity gradient direction (so-called parallel orientation). Shearing at high temperatures near the isotropization temperature leads to the orientation of smectic layers with unit normal perpendicular to both the flow and velocity gradient directions (perpendicular orientation). At the intermediate temperatures, both orientations coexist. The SR-SAXS profile of the parallel oriented sample measured with irradiation along the vorticity direction includes a small peak with a spacing of around 80 A in the velocity gradient direction that is parallel to the chain axis. The long spacing is roughly 5 times larger th...