Electric Field Induced Phase Transitions of Polymer Solutions and Mixtures

小行星9310506 外场的施加会影响聚合物混合物的形态和相行为。 本研究探讨了利用电场对聚合物混合物形态的操纵。 聚合物溶液的初步结果，证明了各种新的现象，如电场诱导的分层和再混合的聚合物混合物。 这些结果表明，有可能系统地控制聚合物共混物的界面性能，和操纵它们的域结构。 这种控制可用于聚合物混合物的加工，以获得特定的本体材料性质并改善界面混合。 该研究将这些初步结果扩展到包括聚合物共混物和聚合物凝胶。 此外，将检查上下临界溶解温度系统，因为预测相边界的具体形状以确定电场的应用是否会导致分层（UCST系统）或重新混合（LCST系统）。 最后，该项目考虑了电场和水动力场的同时应用，因为真实的过程通常包括流动的存在。 由于流体动力也被认为会影响聚合物液体的相行为，因此可以预期电场和流场效应的非线性耦合。 本研究采用实验与理论相结合的方法。 小角光散射和散射二向色性被用来测量受外部流场作用的聚合物混合物的结构。这两种实验方法提供了浓度波动的各向异性的测量，并且可以现场使用。 理论分析利用目前的平均场的方法，浓度波动的动态可以表示在通量的相对重要性，由于外部领域和松弛机制所产生的渗透力。 ***

9310506 Fuller The morphology and phase behavior of polymer mixtures can be influenced by the application of external fields. This research examines the manipulation of polymer mixture morphology by the use of electric fields. Preliminary results on polymer solutions are offered that demonstrate a variety of new phenomena, such as electric field-induced de-mixing and re- mixing of polymer mixtures. These results suggest the possibility of systematically controlling the interfacial properties of polymer blends, and the manipulation of their domain structure. Such control could be used in the processing of polymer mixtures to arrive at specific bulk material properties and improve interfacial mixing. The research extends these preliminary results to include polymer blends and polymer gels. In addition, both upper and lower critical solution temperature systems will be examined, since the specific shape of the phase boundary is predicted to determine whether application of an electric field will cause either de-mixing (UCST systems) or re-mixing (LCST systems). Finally, the project considers the simultaneous application of electric and hydrodynamic fields, since real processes normally include the presence of flow. Since hydrodynamic forces are also known to affect the phase behavior of polymer liquids, a nonlinear coupling of the effects of electric and flow fields would be expected. The research combines experimentation and theory. Small angle light scattering and scattering dichroism are used to measure the structure of polymer mixtures subject to external flow fields Both experiments methods provide measures of anisotropy in concentration fluctuations and can be used in situ. The theoretical analysis utilizes current mean field approaches whereby the dynamics of concentration fluctuations can be expressed in terms of the relative importance of fluxes due to the external fields and relaxation mechanisms arising from osmotic forces. ***