用SAXS/WAXS研究聚氧乙烯/聚氧丁烯嵌段共聚物在n-己烷中的结晶性球形胶束结构

嵌段共聚物在选择性溶剂中能够自组装形成胶束，胶束的不同形状与嵌段共聚物的结构、溶剂和浓度有关．无定形嵌段共聚物通常形成球形胶束，在某些情况下也可以形成其它形状的胶束,关于结晶性嵌段共聚物在无定形链段选择性溶剂中的胶束结构和形状的报道非常少．由于结晶和相似相溶两种作用力的竞争，使得这类胶束的形状丰富多变．通常结晶作用较强时，结晶性嵌段共聚物形成片状的胶束，当结晶组分比较少时，可形成棒状胶束，尽管理论上已经指出存在球形胶束，但尚无关于这方面的报道。

SAXS/WAXS Studies on Structure of Spherical Micelles Formed by Poly (oxyethylene)/poly (oxybutylene) Block Copolymers in n- Hexane

The structure of micelles formed by two poly(oxyethylene)/poly(oxybutylene) block copolymers, E76B38 and E155B76, in n-hexane at 50 ℃ was studied by synchrotron Small Angle X-ray Scattering(SAXS) and Wide Angle X-ray Scattering(WAXS). Spherical micelle with a crystalline core was observed for E155B76. E76B38 also formed spherical micelles, but the core was amorphous. The radius of the core(R), the length of the amorphous chain in the shell(L) and the number of association(N) were obtained by fitting the SAXS data with the model of a spherical core attached with Gaussian chains. The result showed that the E block exhibited multiple folds. The B block tended to be more coiled and the area occupied by per chain was larger in the micelles of E155B76, which are favorable to the formation of spherical micelles.