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首页> 外文期刊>日本レオロジ-学会志 >Rheo-optical Studies of Concentrated PBLG Solutions. IIFlow and Orientation of PBLG Liquid Crystal System
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Rheo-optical Studies of Concentrated PBLG Solutions. IIFlow and Orientation of PBLG Liquid Crystal System

机译：浓缩PBLG溶液的Rheo-光学研究。 PBLG液晶系统的IIFLOW和方向

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Rheo-optical experiments have been carried out to study the relationship between rheological properties and structures of concentrated solutions of PBLG (Poly-γ-Benzyl-L-glutamate) in m-cresol. The flow properties of the solutions at concentrations above B-point have been observed with a rheometer equipped with quartz cone-plate, and simultaneously the transmitted light intensities (Ix, In and IE) of polarized light have been measured on the sample under shear as functions of shear rate (3×10-2-4×100s-1). It has been found that the transmitted light intensity IE (measured under extinction position of crossed polarizers system) is the most meaningful measure to know the orientation behavior and the mesophase transition of polymer liquid crystal systems.IE is very high in the undisturbed state for all the solutions tested.In the case of a 10 wt% solution, IE becomes very low under shear even at low shear rate and rapidly decreases to zero with increasing shear rate. The transmitted light intensities Ix (with crossed polarizers) and I (with parallel polarizers) change with shear rate in a wave-like manner, indicating that the retardation changes continuously with increasing shear rate. From the results, it is concluded that in the case of the 10% solution the polydomain cholesteric structure in the undisturbed state changes easily to a continuous phase of nematic structure even at low shear rate. In the case of a 15 wt% solution, IE decreases from a high value in the undisturbed state to a lower value by shearing and remains almost constant over a certain range of shear rate, until it suddenly decreases to zero at a certain high shear rate where the system changes into a continuous nematic phase. In the case of a 20 wt% solution, IE remains at a rather high level even at high shear rate, indicating that the system undergoes polydomain flow. In the case of a 40 wt% solution, IE remains at a high value even at the highest shear rate examined, and the system is considered to flow maintaining a polydomain cholesteric structure. No large scale orientation of molecules is observed even at high shear rate. The apparent viscosity of the solutions is the lowest among the solutions tested. It is pointed out that the lower viscosity does not always mean the higher degree of molecular orientation.The recovery of IE, after cessation of the steady shear, is negligibly small, if the steady state IE has once reached nearly zero. However, the recovery of IE is quite large, when the steady state IEll has remained at a high value and the system has held its polydomain structure in flow.
机译：已经进行了RHEO-光学实验，以研究M-CRESOL中PBLG（聚-γ-苄基-L-谷氨酸）浓缩溶液的流变性质与结构之间的关系。已经用配备有石英锥板的流变仪观察到高于B点以上B点的溶液的流动性质，并且同时在剪切下的样品上测量偏振光的透射光强度（IX，IN和IE）。剪切速率的功能（3×10-2-4×100s-1）。已经发现，透射光强度IE（在交叉偏振器系统的消光位置测量）是了解聚合物液晶系统的方向行为和中间相转变的最有意义的措施。IE的方向性液晶系统的中间相转变是非常高的测试的溶液在10wt％溶液的情况下，即使在低剪切速率下，也可以在剪切下变得非常低，并且随着剪切速率的增加而迅速降低至零。透射光强度IX（带有交叉偏振器）和I（具有平行偏振器）以波状方式的剪切速率改变，表明延迟随着剪切速率的增加而连续变化。从结果中得出结论，在10％溶液的情况下，即使在低剪切速率下，在未受干扰状态下的多块胆甾型结构也容易变化到向列结构的连续相。在15wt％溶液的情况下，即通过剪切从未受干扰状态的高值降低到较低的值，并且在一定范围的剪切速率下保持几乎恒定，直到它以一定的高剪切速率突然降至零。系统变化为连续的向列阶段。在20wt％溶液的情况下，即使在高剪切速率下也保持在相当高的水平，表明系统经历多域流动。在40wt％溶液的情况下，即使在检查的最高剪切速率下，即使在检查的最高剪切速率也保持高值，并且该系统被认为是保持多域胆甾型结构的流动。即使高剪切速率也没有观察到分子的大规模取向。溶液的表观粘度是测试的溶液中最低的。指出，较低粘度并不总是意味着较高的分子取向程度。如果稳态IE达到近零，则稳定剪切停止后，恢复即，在稳定剪切的停止之后的恢复。然而，当稳态IELL保持高值并且系统以流动保持其多域结构时，IE的恢复非常大。

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