Dynamics and Morphology of Anisotropic Phase Separation of Polymar Blends Cross-linked by Unearly Polarized light.

本课题的研究目的有两个：利用偏振选择性反应诱导聚合物共混物的各向异性相分离和建立聚合物共混物形态控制的新方法。第一个目的是通过使用线性偏振光选择性地诱导二元聚合物共混物组分之间的化学反应来实现的。通过这样做，浓度波动的空间对称性被打破，导致各向异性相分离。为了阐明这种对称性破缺过程对反应共混物的所得形态的后果，在实验中利用了两种典型的反应，即交联和非交联。为了便于实验，在本研究项目中使用具有众所周知的低临界溶解温度（LCST）的聚苯乙烯（P5）和聚（乙烯基甲基醚）（PVME）的混合物。仅对PS组分进行了化学修饰，通过用两种或更多种标记物标记， ...更多信息 外消旋（PSA）或反式-芪（PSS）。PS/P VME共混物不稳定的PSA链之间的交联反应器通过蒽的光二聚化或光异构化的二苯乙烯部分标记的PSS链。用线偏振光照射PSA/PVME和PSS/PVME两种共混物，得到以下结果：[1]在光照射下，发生各向异性相分离，得到几乎垂直于线偏振光方向（E）取向的层状形貌。对于光交联体系，沿着垂直于（E）方向的相分离进行得更快，而对于光异构体系，沿着平行于I（E）方向的相分离发展得最快。[2]所有辐照的共混物在相对于极化（E）的不同取向处表现出不同的临界点。相分离沿沿着不同的取向以不同的速率进行。通过将这些动力学数据与用非偏振光照射B获得的结果进行比较，发现在一定照射下出现的形态是不同不稳定性沿沿着不同取向传播的干涉过程的结果。少

This research project has two purposes : inducing anisotropic phase separation polymer blends by taking advantages of polarization-selective reactions and establishing novel method for morphology control of polymer blends. The first purpose was attained by using linear polarized light to selectively induce chemical reactions between component of binary polymer blends. By doing so, the spatial symmetry of concentration fluctuations is broken, leading to anisotropic phase separation. In order to elucidate the consequence of this symmetry breaking process on the resulting morphology of the reacting blends, two typical reactions, i.e. cross-linking and non-cross-linking , were utilized in the experiments. To facilitate the experiments, mixtures of polystyrene (P5 and poly(vinyl methyl ether) (PVME) which have a well-known lower critical solution temperature (LCST), were used in this research project. Only the PS component was chemically modified for the purpose by labeling with either anth … More racene (PSA) or tram-stilbene (PSS). PS/P VME blends were destabilized by either the cross-linking reactor between PSA chains via photodimerization of anthracene or the photoisomerization of the stilbene moieties labeled on the PSS chains. The following results were obtained b irradiating the two blends PSA/PVME and PSS/PVME with linearly polarized uv light :[1] Upon irradiation, anisotropic phase separation takes place, giving lamella-like morphologies orienting almost perpendicular to the direction (E) of the linearly polarize light, For the photo-cross-linking systems, the phase separation proceeds faster along the direction perpendicular to (E), whereas it evolves fastest along the direction parallel I (E) for the photoisomerizing system.[2] All the irradiated blends exhibit different critical points at different orientation with respect to the polarization (E). The phase separation proceeds with different rates along different orientations. By comparing these kinetic data with the results obtained b irradiation with unpolarized light, it was found that the morphology emerging at a certain irradiation is the consequence of an interference process of different instabilities propagating along different orientations. Less