Synthesis and Structure Properties of Gradient-Modulus Star Copolymers

本项目的目的是研究梯度模数星形共聚物的合成和结构有序性。取得的结果如下：1.研究结果。将聚[异戊二烯(I)-嵌段-I/苯乙烯(S)-嵌段-S]锥形嵌段单阴离子与苯中的二乙烯基苯(DVB)进行交联，制备了梯度模数星形共聚物。用静态和动态光散射(SLS和DLS)表征了这些恒星的稀溶液性质。苯的回转半径与斯托克斯半径之比(R_G/R_H)随臂数的增大而逐渐减小并趋于1。即使是具有多臂的梯度模星，其行为也不像接近硬球体，而是像软球，在良好的溶剂中可以在边缘附近穿透。从DLS结果可以看出，即使在选择性溶剂中，梯度模数星也能形成单分子胶束。通过小角X射线在苯中的散射和透射电子显微镜的测量研究了恒星的结构有序性。所有的恒星样品都在重叠阈值(C‘)附近形成了具有体心立方(Bcc)结构的晶格。在臂数为n&lt；67的星形样品中，这种结构转变为块体薄膜中的片层结构，而在n=289的星形样品中，即使在块状薄膜中，球状结构仍保持着单分子胶束的尺寸，这是一个有趣的趋势。梯度模星在C‘附近形成具有体心立方结构的晶格。这些星体在甲基丙烯酸甲酯(MMA)单体中形成立方晶格后，通过MMA单体的自由基聚合，将永久有序晶格锁定在固体基质中，构建了聚合物超结构。该技术是制备纳米聚合物超结构的最佳方法之一。

The aim of this project is to study the novel synthesis and structural ordering of gradient-modulus star copolymers. The results obtained are as follows.1. Gradient-modulus star copolymers were prepared by crosslinking poly[isoprene(I)-block-I/styrene(S)-block-S] tapered block monoanions with divinylbenzene(DVB) in benzene. The dilute-solution properties of these stars were characterized by static and dynamic light scattering (SLS and DLS). The ratio of radius of gyration over the Stokes radius (R_G/R_H) in benzene decreased gradually and approached unity as the arm number became large. Even gradient-modulus stars with multiarms behave not as near hard spheres but as soft spheres which were penetrable near the edge in a good solvent. It was found from the results of DLS that gradient-modulus stars formed unimolecular micelles even in selective solvent.2. Structural orderings of stars were investigated through the small-angle X-ray scattering in benzene and through the transmission electron microscopy (TEM) measurements. All of the star samples formed a lattice with a body-centered-cubic (BCC) structure near the overlap threshold (C'). In the star specimens with arm number n<67, this structure changed to the lamellae in the bulk film, in the star specimen with n=289, it showed an interesting tendency for the spherical structure to be maintained with the dimension of the unimolecular micelle even in the bulk film.3. Gradient-modulus stars formed a lattice with BCC structure near the C'. After these stars formed a cubic lattice in methyl methacrylate (MMA) monomer, the polymeric superstructures were constructed by locking permanently ordered lattice in a solid matrix by means of free-radical polymerization of MMA monomer. This technique is one of the best methods fir creating nanoscopic polymeric superstructures.