Confined crystallization in lamellae forming poly(3‐(2′‐ethyl)hexylthiophene) (P3EHT) block copolymers
Confined crystallization in lamellae forming poly(3‐(2′‐ethyl)hexylthiophene) (P3EHT) block copolymers
复制标题
形成聚(3-(2-乙基)己基噻吩)(P3EHT)嵌段共聚物的片层中的限制结晶
DOI：
10.1002/polb.23904
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
R. Segalman
中科院分区：
文献类型：
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作者：
E. Davidson;B. Beckingham;Victor Ho;R. Segalman
聚（3-烷基噻吩）（P3 AT）中的电荷传输与微晶的纳米级组织密切相关。嵌段共聚物形态提供了一个理想的平台来研究结晶，因为链端以明确定义的几何形状束缚在已知的界面上。以聚3-（2′-乙基）己基噻吩（P3 EHT）为研究对象，研究了软约束和硬约束对P3 EHT结晶行为的影响.在这里，P3 EHT相对于通常研究的聚（3-己基噻吩）（P3 HT）的较低熔点促进了其受限结晶，使其成为理想的模型系统。虽然透射电子显微镜（TEM）和小角X射线散射（SAXS）显示两组二嵌段在熔体和结晶后均具有良好的有序层状形态，但玻璃态嵌段相对于橡胶态基质嵌段抑制了P3 EHT的受限结晶。通过SAXS和广角X射线散射（WAXS）对对齐的二嵌段的分析表明，P3 EHT链轴垂直于域界面对齐，允许烷基链和平行于层的π-π堆叠方向的优先生长。最后，表明在熔体中二嵌段自组装之后，微晶生长驱动微区的膨胀以匹配P3 EHT轮廓长度。得出的结论是，P3 EHT链采用了扩展的构象内受限的微晶由于刚性性质的聚噻吩相对于柔性链结晶聚合物。© 2015 Wiley Periodicals，Inc. J. Polym.科学，部分B：聚合物物理学2016，54，205-215
Charge transport in poly(3‐alkylthiophene)s (P3AT)s is closely linked to the nanoscale organization of crystallites. Block copolymer morphologies provide an ideal platform to study crystallization as the chain ends are tethered at a known interface in a well‐defined geometry. The impact of soft versus hard confinement on P3EHT crystallization was studied using poly(3‐(2′‐ethyl)hexylthiophene) (P3EHT) containing diblocks with both rubbery poly(methyl acrylate) (PMA) and glassy polystyrene (PS) blocks. Here, P3EHT's lower melting point relative to the commonly studied poly(3‐hexylthiophene) (P3HT) facilitated its confined crystallization and makes it an ideal model system. While transmission electron microscopy (TEM) and small angle X‐ray scattering (SAXS) revealed well‐ordered lamellar morphologies both in the melt and post‐crystallization for both sets of diblocks, the glassy blocks inhibit confined crystallization of P3EHT relative to rubbery matrix blocks. Analysis of aligned diblocks by both SAXS and wide angle X‐ray scattering (WAXS) revealed that the P3EHT chain axis aligns perpendicular to domain interfaces, allowing preferential growth of the alkyl‐chain and π–π stacking directions parallel to lamellae. Finally, it was shown that following diblock self‐assembly in the melt, crystallite growth drives expansion of microdomains to match the P3EHT contour length. It was concluded that P3EHT chains adopted an extended conformation within confined crystallites due to the rigid nature of polythiophenes relative to flexible chain crystalline polymers. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 205–215