Supramolecular ABA triblock copolymer with polyrotaxane as B block and its hierarchical self-assembly
Supramolecular ABA triblock copolymer with polyrotaxane as B block and its hierarchical self-assembly
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DOI：
10.1021/ma800632m
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发表时间：
2008-07-22
期刊：
影响因子：
5.5
通讯作者：
Huang, Jin
中科院分区：
文献类型：
--
作者：
Ren, Lixia;Ke, Fuyou;Huang, Jin
以α-环糊精(α-CDS)为引发剂，聚乙二醇单甲醚为引发剂，通过原子转移自由基聚合(ATRP)，合成了一系列新型超分子聚轮烷ABA三嵌段共聚物。用二维旋转框架Overhauser效应谱(2D ROESY)和X射线衍射仪(XRD)分析了以聚轮烷为B嵌段、聚(二甲氨基)甲基丙烯酸乙酯-b-聚甲基丙烯酸二甲氨基乙酯(DMA-b-PEGCD-b-DMA)三嵌段共聚物的分子结构。用动态光散射(DLS)、静态光散射(SLS)和透射电子显微镜(TEM)研究了共聚物在水溶液中的自组装行为。与不含α-CDS的模型三嵌段共聚物和由Homo-PEG和α-CDS组成的聚假轮烷不同，超分子三嵌段共聚物在水中自组装成具有无定形核心的球体。此外，嵌段共聚物在酸性水溶液中侧链被质子化，生成了以六角堆积的聚轮烷为核心的颗粒。有趣的是，在溶剂挥发的作用下，颗粒进一步聚集成大圆盘。
A series of novel well-defined supramolecular ABA triblock copolymers of polyrotaxane are synthesized via atom transfer radical polymerization (ATRP) of 2-(dimethylamino)ethyl methacrylate (DMA) initiated by a polypseudorotaxane initiator of alpha-cyclodextrins (alpha-CDs) and PEG. The molecular structure of the ABA triblock copolymer with a polyrotaxane as B block, poly(2-(dimethylamino)ethyl methacrylate)-b-PEG[included by alpha-CDs]-b-poly(2-(dimethylamino)ethyl methacrylate) (DMA-b-PEGCD-b-DMA), was confirmed by two-dimensional rotating frame Overhauser effect spectroscopy (2D ROESY) and X-ray diffraction (XRD) analyses. Self-assembly behaviors of the copolymers in water solution were studied by dynamic light scattering (DLS), static light scattering (SLS), and transmission electron microscopy (TEM). Different from the model triblock copolymer without alpha-CDs and the polypseudorotaxanes composed of homo-PEG and alpha-CDs, the supramolecular triblock copolymers in water self-assembled into spheres with an amorphous core. Furthermore, the block copolymers at an acidic aqueous solution where the flanking chains were protonated generated the particles with a core of hexagonally packed polyrotaxanes. It is interesting to notice that the particles further aggregated into large disks induced by the solvent evaporation.