Bai Lubing, Han Yamin, Sun Chen, An Xiang, Wei Chuanxin, Liu Wei, Xu Man, Sun Lili, Sun Ning, Yu Mengna, Zhang He, Wei Qi, Xu Chunxiang, Yang Yingguo, Qin Tianshi, Xie Linghai, Lin Jinyi, Huang Wei
Center for Supramolecular Optoelectronics (CSO), Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing 211816, China.
State Key Laboratory of Bioelectronics, School of Electronic Science and Medical Engineering, Southeast University, Nanjing 210096, China.
Research (Wash D C). 2020 Sep 30;2020:3405826. doi: 10.34133/2020/3405826. eCollection 2020.
The intrinsically rigid and limited strain of most conjugated polymers has encouraged us to optimize the extensible properties of conjugated polymers. Herein, learning from the hydrogen bonds in glucose, which were facilitated to the toughness enhancement of cellulose, we introduced interchain hydrogen bonds to polydiarylfluorene by amide-containing side chains. Through tuning the copolymerization ratio, we systematically investigated their influence on the hierarchical condensed structures, rheology behavior, tensile performances, and optoelectronic properties of conjugated polymers. Compared to the reference copolymers with a low ratio of amide units, copolymers with 30% and 40% amide units present a feature of the shear-thinning process that resembled the non-Newtonian fluid, which was enabled by the interchain dynamic hydrogen bonds. Besides, we developed a practical and universal method for measuring the intrinsic mechanical properties of conjugated polymers. We demonstrated the significant impact of hydrogen bonds in solution gelation, material crystallization, and thin film stretchability. Impressively, the breaking elongation for P4 was even up to ~30%, which confirmed the partially enhanced film ductility and toughness due to the increased amide groups. Furthermore, polymer light-emitting devices (PLEDs) based on these copolymers presented comparable performances and stable electroluminescence (EL). Thin films of these copolymers also exhibited random laser emission with the threshold as low as 0.52 J/cm, suggesting the wide prospective application in the field of flexible optoelectronic devices.
大多数共轭聚合物固有的刚性和有限的应变促使我们优化共轭聚合物的可拉伸性能。在此，借鉴葡萄糖中的氢键（其有助于提高纤维素的韧性），我们通过含酰胺侧链将链间氢键引入聚二芳基芴。通过调节共聚比，我们系统地研究了它们对共轭聚合物的分级凝聚结构、流变行为、拉伸性能和光电性能的影响。与酰胺单元比例较低的参比共聚物相比，酰胺单元含量为30%和40%的共聚物呈现出类似非牛顿流体的剪切变稀过程特征，这是由链间动态氢键实现的。此外，我们开发了一种实用且通用的方法来测量共轭聚合物的本征力学性能。我们证明了氢键在溶液凝胶化、材料结晶和薄膜拉伸性方面的显著影响。令人印象深刻的是，P4的断裂伸长率甚至高达约30%，这证实了由于酰胺基团增加，薄膜的延展性和韧性得到了部分增强。此外，基于这些共聚物的聚合物发光器件（PLED）表现出可比的性能和稳定的电致发光（EL）。这些共聚物的薄膜还表现出阈值低至0.52 J/cm的随机激光发射，表明在柔性光电器件领域具有广阔的应用前景。
