Spherical polymer brushes in solvents of variable quality: an experimental insight by TEM imaging.
Spherical polymer brushes in solvents of variable quality: an experimental insight by TEM imaging.
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DOI：
10.1021/la400016z
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发表时间：
2013-03
期刊：
影响因子：
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通讯作者：
Qian Zhang;Y.-T. Liao;Lipeng He;W. Bu
中科院分区：
文献类型：
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作者：
Qian Zhang;Y.-T. Liao;Lipeng He;W. Bu
由[PW12O40](3-)和聚(苯乙烯-b-4-乙烯基吡啶甲基碘)组成的球形胶束和囊泡被视为研究不同质量溶剂中球形聚合物刷(SPB)的模型系统。在氯仿溶液和甲醇体积比为9.1%的氯仿/甲醇混合物中，刷链发生纯排斥，其中接枝聚苯乙烯链具有相对伸长的构象。甲醇浓度的进一步增加导致刷内/刷间范德华引力的存在。透射电子显微镜研究表明，分离的、寡聚的SPB和多SPB聚集体(MSA)共存，甲醇含量为17%至23%。随着甲醇含量的增加，仅检测到 MSA。在分离的寡聚 SPB 和 MSA 中，冠和核均显着收缩。在寡聚 SPB 和 MSA 的核心之间观察到接枝链的完全相互渗透。
The spherical micelle and vesicle composed of [PW12O40](3-) and poly(styrene-b-4-vinylpyridinium methyl iodide) are regarded as a model system to study spherical polymer brushes (SPBs) in solvents of various quality. The pure repulsions occur for the brush chains in the chloroform solution and chloroform/methanol mixture with a methanol volume ratio of 9.1%, where the grafted polystyrene chains have a relatively extended conformation. Further increase in the methanol concentrations leads to the presence of the intra/inter-brush van der Waals attractions. Transmission electron microscopy studies show that there is a coexistence of isolated and oligomeric SPBs and multi-SPB aggregates (MSAs) with the methanol content from 17% to 23%. Only MSAs are detected with the increasing methanol content. Both the corona and core shrink significantly in the isolated and oligomeric SPBs and MSAs. The full interpenetration of the grafted chains is observed between the cores in the oligomeric SPBs and MSAs.