Heteroarm Star-Branched Block Copolymers

杂臂星星聚合物含有n个臂，其中x个臂是 包括单体A，而n-x臂包括单体B。 这些星形聚合物是全新的有机材料， 化学结构 最近的理论研究预测， 表现出不寻常的偏析和相间现象。 合成 将制定程序，以准备这些新的 n = 3，4的材料，具有精确定义的结构， 用于在自由端连接特殊官能团 在B臂上。 研究表明， 孤立的杂臂恒星将从速率和 大环化平衡，从激基缔合物推导 两臂自由携带芘的分子发射 形接头. 不同类型臂间的区别 在半稀释溶液、熔体和 固体状态将用杂臂星来确定 选择性标记用于研究激基缔合物发射或 非辐射单重态能量转移。 孤立的动力学 杂臂恒星，以及它们在集中的 溶液和熔体，将使用脉冲梯度 自旋回波核磁共振

Heteroarm star polymers contain n arms, of which x arms are comprised of monomer A while n-x arms are comprised of monomer B. These star-shaped polymers are organic materials of entirely new chemical structure. Recent theoretical work predicts they will exhibit unusual segregation and interphase phenomena. Synthetic procedures will be developed for preparation of these new materials with n = 3,4 with precisely defined architectures and for the attachment of special functional groups at the free ends of the B arms. The consequences of interarm interactions in isolated heteroarm stars will be assessed from the rates and equilibrium for macrocyclization, as deduced from excimer emission by molecules in which two arms bear pyrene at their free ends. Discrimination among the various types of interarm interactions that can occur in semidilute solution, melts, and in the solid state will be determined with heteroarm stars selectively labelled for study of excimer emission or the rate of nonradiative singlet-energy transfer. The dynamics of isolated heteroarm stars, as well as their diffusion in concentrated solutions and melts, will be determined using pulsed-gradient spin-echo nuclear magnetic resonance.