Conformational Dynamics of Block Copolymer Liquids

嵌段共聚物在各种材料中的应用越来越多 应用程序，主要是由于属性来自 块之间的热力学相互作用。 随着链条的增加 长度和/或相互作用强度，嵌段共聚物液体经历 有序-无序转变（ODT）到微结构化状态。 虽然已经了解了很多关于可访问的形态， 强分离极限，即，进入有序状态， ODT附近的行为，即，弱偏析 限制，就更不容易理解了。 我们将使用强大的光学 技术，振荡流双折射（OFB），以诊断 并表征ODT和相关联的次序-次序转换。 此外，广泛的计算表明，稀释- 嵌段共聚物的溶液OFB性质是唯一敏感的 到各种块的长度和链位置;两者 否则很难确定数量。 我们将探讨 OFB作为块特征化工具潜力 共聚物，并且在这样做时评估嵌段-嵌段共聚物的影响。 弛豫谱上的相互作用。 最后，调查 将继续溶剂在构象中的作用 动力学实验，如OFB，无论是在溶剂动力学方面 和溶剂质量。 尤其是， 溶剂旋转弛豫和高频 聚合物溶液的粘弹性将被检查 进一步.

Block copolymers enjoy increasing use in a wide range of materials applications, due primarily to properties derived from the thermodynamic interactions between blocks. With increasing chain length and/or interaction strength, block copolymer liquids undergo an order-disorder transition (ODT) to a microstructured state. Although much has been learned about the accessible morphologies in the strong-segregation limit, i.e., well into the ordered state, the behavior in the vicinity of the ODT, i.e., the weak-segregation limit, is much less understood. We will use a powerful optical technique, oscillatory flow birefringence (OFB), to both diagnose and characterize the ODT and associated order-order transitions. In addition, extensive calculations have shown that the dilute- solution OFB properties of block copolymers are uniquely sensitive to the lengths and chain locations of the various blocks; both quantities are otherwise difficult to determine. We will explore the potential of OFB as a characterization tool for block copolymers, and in so doing assess the effect of the block-block interaction on the relaxation spectrum. Finally, the investigation will be continued of the role of the solvent in conformational dynamics experiments such as OFB, both in terms of solvent dynamics and solvent quality. In particular, a remarkable relationship between solvent rotational relaxation and the high-frequency viscoelastic properties of polymer solutions will be examined further.