Theoretical Modelling of Hierarchically Associated Structures inHydrophobically Modified PNIPAM Aqueous Solutions on the Basis of a Neutron Scattering Study
Theoretical Modelling of Hierarchically Associated Structures inHydrophobically Modified PNIPAM Aqueous Solutions on the Basis of a Neutron Scattering Study
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基于中子散射研究的疏水改性 PNIPAM 水溶液中分层关联结构的理论建模
DOI：
10.1002/masy.201050521
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发表时间：
2010
影响因子：
--
通讯作者：
and Fran.coise M.Winnik
中科院分区：
文献类型：
--
作者：
Tsuyoshi Koga;Fumihiko Tanaka;Ryuhei Motokawa;Satoshi Koizumi;and Fran.coise M.Winnik
基于小角中子散射数据，我们建立了一个在水溶液中携带十八烷基端基的遥爪聚（N-异丙基丙烯酰胺）（PNIPAM）自组装的理论模型，该模型是温度和浓度的函数。在浓度为10 g L-1、温度为10至20 °C的溶液中，分子量为22，200 g mol-1的遥爪PNIPAM以含有约12条聚合物链的花状胶束形式缔合。胶束具有3层核壳形态，其中内核由十八烷基单元组成，致密的内壳由部分塌陷的PNIPAM链组成，外壳由溶胀的水合PNIPAM链组成。加热到31 °C以上的溶液的散射曲线的急剧变化归因于由约1000个聚合物链组成的直径为100 nm的介晶的形成。在较低浓度（1 g L−1）的溶液中，花胶束和介孔分子的结合受到抑制。单个花胶束和介体的结构不受浓度变化的影响。在50 g L−1的溶液中，在低温（10 °C）下的散射曲线中出现了归因于花状胶束之间相关性的峰。尽管胶束间桥的数量不同，但在50 g L− 1下散射曲线的总体温度依赖性与10 g L−1下的相似。
We developed a theoretical model for a self‐assembling telechelic poly(N‐isopropylacrylamide) (PNIPAM) carrying octadecyl end‐groups in aqueous solution, as a function of temperature and concentration, on the basis of small‐angle neutron scattering data. In solutions of concentration 10 g L−1at temperatures between 10 and 20 °C, the telechelic PNIPAM of molecular weight of 22,200 g mol−1associates in the form of flower micelles containing about 12 polymer chains. Micelles have a 3‐layered core‐shell morphology with an inner core consisting of the octadecyl units, a dense inner shell consisting of partly collapsed PNIPAM chains, and an outer shell of swollen hydrated PNIPAM chains. Drastic changes in the scattering profile of the solution heated above 31 °C are attributed to the formation of mesoglobules of diameter of 100 nm consisting of about 1000 polymer chains. In solutions of lower concentration (1 g L−1), association of flower micelles and mesoglobules is suppressed. The structure of the individual flower micelles and mesoglobules is not affected by changes in concentration. In solutions of 50 g L−1, a peak attributed to a correlation between flower micelles appears in the scattering profiles at low temperature (10 °C). Despite the difference in the population of intermicellar bridges, the overall temperature dependence of the scattering profile at 50 g L−1remains similar to that at 10 g L−1.