Solvent-induced crystallization of spherical micelles formed by copolymer blends
Solvent-induced crystallization of spherical micelles formed by copolymer blends
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DOI：
10.1021/ma060799k
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发表时间：
2006-10
期刊：
影响因子：
5.5
通讯作者：
Weihuan Huang;Chunxia Luo;Bin-yao Li;Yanchun Han
中科院分区：
文献类型：
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作者：
Weihuan Huang;Chunxia Luo;Bin-yao Li;Yanchun Han
我们跟踪了聚苯乙烯-b-聚丙烯酸(PS-b-PAA)和polystyrene-b-poly(2-vinylpyridine)b-poly(ethylene氧化物(PS-b-P2VP-b-PEO)(球形胶束的核心是在中性溶剂N，N-二甲基甲酰胺、二甲基甲酰胺中通过氢键形成的)混合物(PS-b-PAA)经DMF蒸气处理形成的球形胶束的形态演变和结晶过程。胶束膜在DMF中处理不同时间，可观察到膜破裂、圆柱状聚集体形成、规则的方形片层等现象。在DMF蒸气中退火的早期，胶束膜变得不稳定并破裂。在这一阶段，PEO单晶成核前形成的圆柱状聚集体，其中的PEO嵌段实现了缔合和初级链折叠，形成了中间相。在DMF蒸气中进一步处理导致PEO块在准正方形片层的拐角处成核。然后，胶束薄膜在DMF蒸气中进行充分的退火，形成相当规则的“三明治”片层结构，该结构由PEO单晶层由上下晶体基面上的两层其他无定形块连接而成。
We have followed the morphological evolution and crystallization process of spherical micelles formed by the mixture of polystyrene-b-poly(acrylic acid) (PS-b-PAA) and polystyrene-b-poly(2-vinylpyridine)b-poly(ethylene oxide) (PS-b-P2VP-b-PEO) (the core of the spherical micelles was made of P2VP and PAA blocks through hydrogen bonding in neutral solvent N,N-dimethylformamide, DMF) via DMF vapor treatment. Different phenomena, such as rupture of the film, formation of cylinder aggregates and regular square lamellae, were observed when the micelle film was treated in DMF for different times. At the early stage of annealing in DMF vapor, the micelle film became unstable and ruptured. Cylinder aggregates, within which the PEO blocks achieved the association and primary chain folding, formed as the mesophases before the nucleation of the PEO single crystals at this stage. Further treatment in DMF vapor resulted in the nucleation of the PEO blocks at the corners of quasi-square lamellae. Then a quite regular "sandwich" lamellar structure, constructed by a PEO single-crystal layer covered by two tethered layers of other amorphous blocks on the top and bottom crystal basal surfaces, formed when the film of micelles was annealed in DMF vapor for sufficient times.