Photo-triggered solvent-free metamorphosis of polymeric materials.
Photo-triggered solvent-free metamorphosis of polymeric materials.
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DOI：
10.1038/s41467-017-00679-1
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发表时间：
2017-09-11
影响因子：
16.6
通讯作者：
Toyota T
中科院分区：
文献类型：
--
作者：
Honda S;Toyota T
材料的液化和固化是在热相变过程中观察到的最基本的变化，然而，显示等温可逆液体-非液体转化的有机和聚合物软材料的设计仍然具有挑战性。在这里，我们证明了无溶剂的可重复的分子结构之间的转换液体星形和非液体网络聚合物，依赖于裂解和改造的共价键在hexaarylbiimidazole。首次合成了含2，4，5-三苯基咪唑端基的四臂星形聚丙烯酸丁酯和聚二甲基硅氧烷。随后将2，4，5-三苯咪唑氧化成2，4，5-三苯咪唑基自由基，并将它们与这些液体星星聚合物偶联形成六芳基双咪唑，得到相应的非液体网络聚合物。所得的非液体网络聚合物在UV照射后液化，并产生具有2，4，5-三苯基咪唑基自由基端基的液体星形聚合物，所述星形聚合物在终止UV照射后立即通过所产生的2，4，5-三苯基咪唑基自由基的再偶联再次恢复为非液体网络聚合物。显示等温可逆液体-非液体转化的有机和聚合物软材料的设计具有挑战性。在这里，作者显示了无溶剂的可重复的分子结构之间的转换，液体星型和非液体网络聚合物的裂解和重组的共价键的聚合物链。
Liquefaction and solidification of materials are the most fundamental changes observed during thermal phase transitions, yet the design of organic and polymeric soft materials showing isothermal reversible liquid–nonliquid conversion remains challenging. Here, we demonstrate that solvent-free repeatable molecular architectural transformation between liquid-star and nonliquid-network polymers that relies on cleavage and reformation of a covalent bond in hexaarylbiimidazole. Liquid four-armed star-shaped poly(n-butyl acrylate) and poly(dimethyl siloxane) with 2,4,5-triphenylimidazole end groups were first synthesized. Subsequent oxidation of the 2,4,5-triphenylimidazoles into 2,4,5-triphenylimidazoryl radicals and their coupling with these liquid star polymers to form hexaarylbiimidazoles afforded the corresponding nonliquid network polymers. The resulting nonliquid network polymers liquefied upon UV irradiation and produced liquid star-shaped polymers with 2,4,5-triphenylimidazoryl radical end groups that reverted to nonliquid network polymers again by recoupling of the generated 2,4,5-triphenylimidazoryl radicals immediately after terminating UV irradiation. The design of organic and polymeric soft materials showing isothermal reversible liquid–nonliquid conversion is challenging. Here, the authors show solvent-free repeatable molecular architectural transformation between liquid-star and non-liquid-network polymers by the cleavage and reformation of covalent bonds in the polymer chain.
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影响因子：
5.5
作者：
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作者：
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