Self-association of water-soluble fluorinated diblock copolymers in solutions.
Self-association of water-soluble fluorinated diblock copolymers in solutions.
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DOI：
10.1016/j.jcis.2004.03.046
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发表时间：
2004-08
影响因子：
9.9
通讯作者：
Hiroshi Ito;T. Imae;Tetsuya Nakamura;Motoyuki Sugiura;Y. Oshibe
中科院分区：
文献类型：
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作者：
Hiroshi Ito;T. Imae;Tetsuya Nakamura;Motoyuki Sugiura;Y. Oshibe
用光散射、电位法、原子力显微镜和透射电子显微镜研究了氟化二嵌段共聚物聚（甲基丙烯酸）-嵌段聚（全氟辛基乙基甲基丙烯酸酯）（PMAA-b-PFMA）在水中的自缔合。聚合物胶束的大小随着PMAA块解离程度的增加而增加。由于带电荷的PMAA块体呈拉伸结构，PMAA-b- pfma块体的空间位阻较低，容易形成大的胶束。NaCl的加入屏蔽了PMAA链中的静电斥力，由于PMAA链在胶束的外壳中具有较大的结构，使得PMAA链形成的胶束比无NaCl的水更小。PMAA-b-PFMA在乙醇中的胶束比聚甲基丙烯酸正丁酯-聚全氟辛基甲基丙烯酸乙酯（PtBMA-b- pfma）在乙醇中的胶束大，这是由于PtBMA的位阻更高。对胶束核和壳的尺寸进行了估计。PMAA-b- pfma在水中的胶束具有较厚的壳层和较大的分子体积，与PMAA链的延伸相一致。另一方面，在PtBMA-b-PFMA的乙醇溶液中，胶束的外壳很薄，但具有很大的表面积。这与PtBMA块体在弱溶剂条件下的收缩结构一致。
The self-association of the fluorinated diblock copolymer, poly(methacrylic acid)–block–poly(perfluorooctylethyl methacrylate) (PMAA-b-PFMA), in water has been investigated by light scattering, potentiometry, atomic force microscopy, and transmission electron microscopy. The size of the polymer micelles increases, as the degree of dissociation of the PMAA blocks increases. Since the charged PMAA block takes the stretched structure, PMAA-b-PFMA can easily form large micelles due to the low steric hindrance of PMAA blocks. Addition of NaCl shielded electrostatic repulsion in the PMAA chain and induced the formation of smaller micelles than water without NaCl did because of the bulky structure of the PMAA chain in the shell of the micelles. The micelle of PMAA-b-PFMA in ethanol is larger than that of poly(t-butyl methacrylate)–block–poly(perfluorooctylethyl methacrylate) (PtBMA-b-PFMA) in ethanol as a result of the higher steric hindrance of the PtBMA block. The dimensions of the core and shell of the micelles were estimated. The micelle of PMAA-b-PFMA in water possesses a rather thick shell and a large volume per molecule, consistent with the extended PMAA chain. On the other hand, the shell of the micelle in an ethanol solution of PtBMA-b-PFMA is thin but has a large surface area. Facts are consistent with the shrunk structure of the PtBMA block in poor solvent.