聚甲基丙烯酸甲酯接枝聚氧乙烯在甲苯中的聚集态结构

The Aggregation Structure of PMMA-g-PEO in Toluene

聚甲基丙烯酸甲酯接枝聚氧乙烯 (PMMA-g-PEO)在甲苯中的核磁共振 (NMR)图谱表明甲苯是一种选择性溶剂 ,在甲苯中 PMMA-g-PEO形成的是以支链聚氧乙烯 (PEO)为核 ,以主链聚甲基丙烯酸甲酯(PMMA)为壳的反相胶束 .透射电子显微镜 (TEM)、动态激光光散射 (DLS)和粘度测定结果进一步表明浓度和温度决定着 PMMA-g-PEO在甲苯中的聚集态结构 ,随着温度的升高 ,胶束可以在更低的浓度下形成 .在一定的浓度和温度范围内有下列变化过程 :单分子溶液 增大浓度减小浓度 小反相胶束 增大浓度减小浓度 大反相胶束大反相胶束 升温降温 小反相胶束 升温降温

The NMR results indicated that toluene is a selective solvent for amphiphilic graft copolymer poly(methyl methylacrylate) g poly(ethylene oxide)(PMMA g PEO). The reversed micelles were formed in toluene with PEO side chains as core and PMMA backbones as shells. TEM, DLS and viscosity measurement revealed that the aggregation structure is dependent on the temperature and concentration of the PMMA g PEO solution, at higher temperature the reversed micelle can be formed in a lower concentration. The aggregation structure is changed in a certain range of concentration and temperature, as shown in following schemes. (1) Single molecular solution increasing concn.decreasing concn. Small reversed micelle increasing concn.decreasing concn. Large reversed micelle (2) Large reversed micelle increasing temp.decreasing temp. Smalle reversed micelle increasing temp.decreasing temp. Single molecular solution