Synthesis and Solution Properties of a Rigid Helical Star Polymer: Three-Arm Star Poly(quinoxaline-2,3-diyl)

Six semiflexible helical three-arm star poly­[5,8-dimethyl-6,7-bis­(propoxy­methyl)­quinoxaline-2,3-diyl] (A3PQ) samples which have different arm lengths ranging in the weight-average molar mass Mw from 1.5 × 104 to 2.5 × 105 g mol–1 were synthesized via the living polymerization of the corresponding 1,2-diisocyanobenzene using a trifunctional palladium initiator. The particle scattering function P(q), the z-average mean-square radius of gyration ⟨S2⟩z, and the intrinsic viscosity [η] for the A3PQ samples were determined from light and small-angle X-ray scattering and viscosity measurements in tetrahydrofuran at 25 °C. The obtained data were compared with modern theories for the wormlike star. The experimental P(q) data were represented by the wormlike star model connected with a universal joint. The other data were comparably explained by the same model.

本研究通过三官能团钯引发剂对相应1,2-二异氰基苯进行活性聚合，合成了六种半柔性螺旋形三臂星形聚[5,8-二甲基-6,7-双(丙氧基甲基)喹喔啉-2,3-二基]（A3PQ）样品，其臂长各异，重均摩尔质量（weight-average molar mass, Mw）范围为1.5×10⁴ 至2.5×10⁵ g·mol⁻¹。针对该系列A3PQ样品，于25 ℃的四氢呋喃（tetrahydrofuran, THF）溶剂中，通过光散射、小角X射线散射以及黏度测量，分别测定了其粒子散射函数P(q)、z均方回转半径⟨S²⟩_z 与特性黏度[η]。将所得实验数据与蠕虫状星形聚合物的现代理论进行对比分析，其中实验测得的P(q)数据可通过带有万向节连接的蠕虫状星形聚合物模型进行表征，其余实验数据亦可通过同一模型得到合理解释。