The molecular orientation of π-conjugated polymers is a significant factor for the electrical properties of polymer-based printable devices, because π-conjugated polymers exhibit a notable fast carrier transport property along their main chain. Although various coating processes are suggested, the challenge to realize high-degree alignment by one-step coating without pre- or post-treatments still remains. In this paper, it is reported on the fabrication of an extremely highly aligned thin film by a slow bar coating process using a donor–acceptor π-conjugated polymer with great aggregability. The 2D order parameter achieved is 0.9, which is the highest obtained among the alignment methods with a one-step coating process. Furthermore, the direction of the main chain is selectively oriented parallel or perpendicular to the coating direction depending on the solution concentration with high orientation degree. This unique orientation phenomenon seems to be related to the nematic liquid crystallinity of poly[2,5-(2-octyldodecyl)-3,6-diketopyrrolopyrrole-alt-5,5-(2,5-di(thien-2-yl)thieno [3,2-b]thiophene)] aggregates formed by the slow coating process. The orientation dynamics is discussed by taking the structure and behavior of the aggregates in the solution into account.

中文翻译：

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由慢棒涂布工艺诱导的供体-受体共轭聚合物的方向选择性超高取向状态

π-共轭聚合物的分子取向是聚合物基可印刷器件电性能的重要因素，因为 π-共轭聚合物沿其主链表现出显着的快速载流子传输特性。尽管提出了各种涂层工艺，但在没有预处理或后处理的情况下通过一步涂层实现高度对准的挑战仍然存在。在本文中，报道了使用具有良好聚集性的供体 - 受体 π 共轭聚合物，通过缓慢的棒涂工艺制造高度排列的薄膜。获得的二维有序参数为 0.9，这是在采用一步涂层工艺的对准方法中获得的最高值。此外，主链的方向有选择地平行或垂直于涂层方向取向，这取决于具有高取向度的溶液浓度。这种独特的取向现象似乎与 poly[2,5-(2-octyldodecyl)-3,6-diketopyrrolopyrrole-alt-5,5-(2,5-di(thien-2-yl)-3,6-diketopyrrolopyrrole-alt-5,5-(2,5-di(thien-2-yl) ) 噻吩 [3,2-b] 噻吩)] 聚集体由缓慢的涂覆过程形成。通过考虑解决方案中聚集体的结构和行为来讨论取向动力学。