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通过原子转移自由基聚合合成了由聚甲基丙烯酸甲酯和聚乙二醇链段组成的嵌段共聚物PMMA291-b-PEO114和PMMA120-b-PEO227-b-PMMA120,其中PEO链段是表面活性且水溶性的,而PMMA链段是表面活性但非水溶性的.研究了两种嵌段共聚物在空气/水界面上的界面行为,结果表明它们都能形成具有两个明显转化点的单层膜,第一个转化点在10mN/m,对应于PEO从煎饼型构象向刷型构象转变;另一个转化点在18mN/m,对应于PMMA的紧密排列.利用原子力显微镜(AFM)、扫描电子显微镜(SEM)等表征手段观测了压缩过程中不同压力下形成的表面聚集形貌,发现低压下形成的是典型的PEO脂质体形貌,压缩后形成的是以球形为主体的表面形貌.所不同的是,两嵌段共聚物易发生链折叠,三嵌段共聚物易形成球形胶束结构.
The block copolymers PMMA291-b-PEO114 and PMMA120-b-PEO227-b-PMMA120 composed of polymethylmethacrylate and polyethylene glycol segments were synthesized by atom transfer radical polymerization, in which the PEO segment was the surface Active and water-soluble, whereas the PMMA segments are surface active but not water-soluble.The interfacial behavior of the two block copolymers at the air / water interface was studied and the results showed that both could form a copolymer with two distinct transition points The first transition point at 10 mN / m corresponds to the transition of PEO from pancake-type conformation to brush-type conformation, the other at 18 mN / m, which corresponds to the close arrangement of PMMA.Using atomic force microscopy (AFM) Scanning electron microscopy (SEM) and other characterization means were observed under different pressures during the compression of the formation of surface aggregation morphology and found that the formation of low pressure is typical of PEO liposomes, compressed to form a spherical surface The difference is that the two block copolymers prone to chain folding, triblock copolymer easy to form spherical micellar structure.