Spatial distribution of hydrophobic compounds in polymer micelles as explored by anomalous small-angle X-ray scattering near Br K-edge
Spatial distribution of hydrophobic compounds in polymer micelles as explored by anomalous small-angle X-ray scattering near Br K-edge
复制标题
通过 Br K 边缘附近的反常小角 X 射线散射探索聚合物胶束中疏水性化合物的空间分布
DOI：
10.1016/j.eurpolymj.2015.12.024
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发表时间：
2016
影响因子：
6
通讯作者：
Isamu Akiba
中科院分区：
文献类型：
--
作者：
Ryosuke Nakanishi;Masaki Kinoshita;Shota Sasaki;Isamu Akiba
溴标记的疏水性分子，9-溴芴（BrFL）或2-溴异丁酸乙酯（BrEB），掺入由亲水性聚（N,N-二甲基氨基乙基甲基丙烯酸酯）和疏水性聚（甲基丙烯酸甲酯）（PDMAEMA-b-PMMA）组成的两亲性嵌段共聚物的胶束中，通过Br K边缘附近的反常小角X射线散射（ASAXS）探索了其空间分布。 ASAXS 分析表明，BrFL 集中在疏水性 PMMA 核心内的小区域中，而 BrEB 具有与 PMMA 重复单元相似的分子结构，均匀分散在 PMMA 核心中。 BrFL 在 PMMA 核心内小区域的浓度被解释为由于 BrFL 分子与渗透到 PMMA 核心的水分离。另一方面，由于BrEB的分子结构与PMMA的重复单元相似，BrEB分子均匀地分散在PMMA核中。这项工作的结果表明，聚合物胶束中疏水化合物空间分布的差异是由聚合物胶束疏水核中疏水分子与其他组分（例如疏水聚合物和溶剂）之间的分子间相互作用的差异引起的。
Spatial distributions of bromine-labeled hydrophobic molecules, 9-bromofluorene (BrFL) or ethyl 2-bromoisobutylate (BrEB), incorporated in micelles of amphiphilic block copolymers composed of hydrophilic poly(N,N-dimethylaminoethyl methacrylate) and hydrophobic poly(methyl methacrylate) (PDMAEMA-b-PMMA) were explored with anomalous small-angle X-ray scattering (ASAXS) near Br K-edge. ASAXS analyses clarified that BrFL was concentrated into small domain within hydrophobic PMMA core, whereas BrEB, which had similar molecular structure to the repeating unit of PMMA, was homogeneously dispersed in PMMA core. The concentration of BrFL into small domain within PMMA core was interpreted due to segregation of BrFL molecules from water penetrating into the PMMA core. On the other hand, the BrEB molecules were homogeneously dispersed in the PMMA cores because the molecular structure of BrEB was similar to the repeating unit of PMMA. The results in this work indicated that the differences of spatial distributions of hydrophobic compounds in polymer micelles were derived by the differences of intermolecular interactions between the hydrophobic molecules and the other components, such as a hydrophobic polymer and solvent, in hydrophobic cores of polymer micelles.