High Efficiency Luminescent Liquid Crystalline Polymers Based on Aggregation-Induced Emission and "Jacketing" Effect: Design, Synthesis, Photophysical Property, and Phase Structure
High Efficiency Luminescent Liquid Crystalline Polymers Based on Aggregation-Induced Emission and "Jacketing" Effect: Design, Synthesis, Photophysical Property, and Phase Structure
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基于聚集诱导发射和“夹套”效应的高效发光液晶聚合物：设计、合成、光物理性质和相结构
DOI：
10.1021/acs.macromol.7b01605
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发表时间：
2017-12-26
期刊：
影响因子：
5.5
通讯作者：
Xie, He-Lou
中科院分区：
文献类型：
--
作者：
Guo, Yang;Shi, Dong;Xie, He-Lou
通过在侧基上引入四苯乙烯，成功设计并合成了一系列基于聚集诱导发射（AIE）和“护套”效应的高效发光液晶聚合物（LLCP），即聚{2,5-双{[2-(4-氧四苯乙烯)-正烷基]氧羰基}苯乙烯}（记为Pm，m = 2, 4, 6, 8, 10, 12）不同长度的垫片。由于 AIE 效应，所得的 LLCP 完全不会发生聚集引起的猝灭。通过紫外-可见吸收光谱、光致发光光谱（PL）、偏光显微镜（PLM）、差示扫描量热法（DSC）和变温一维广角X射线衍射（1D WAXD）等技术研究了光物理性质和相行为。结果表明，所得单体表现出典型的 ATE 行为，聚合物表现出聚集增强发射 (AEE) 行为。此外，由于“夹套”效应，聚合物在液晶态下表现出高效发光，这显着依赖于间隔物长度（随着间隔物长度的增加，固态量子产率从52％下降到18％）。同时，玻璃化转变温度（T-g）随着间隔物长度的增加而降低。随着间隔柱长度的增加，相结构从近晶A (SmA) (Pms, m = 2, 4, 6)转变为六方柱状相(Col(H)) (Pms, m = 8, 10, 12)。所有聚合物均表现出良好的成膜性能和加工性能，使其成为有前景的发光器件材料。
A series of high efficiency luminescent liquid crystalline polymers (LLCPs) based on aggregation-induced emission (AIE) and the "Jacketing" effect, namely, poly{2,5-bis{[2-(4-oxytetraphenylethylene)-n-alkyl] oxycarbonyl}styrene} (denoted as Pm, m = 2, 4, 6, 8, 10, 12), were successfully designed and synthesized via introducing tetraphenylethylene to the side group with different length spacers. Because of the AIE effect, the resultant LLCPs are completely free of aggregation caused quenching. The photophysical properties and phase behavior were studied via various techniques such as UV-vis absorption spectra, photoluminescence spectra (PL), polarized light microscopy (PLM), differential scanning calorimetry (DSC), and variable temperature one-dimensional wide-angle X-ray diffraction (1D WAXD). The results revealed that the resultant monomers showed typical ATE behavior and the polymers exhibited aggregation enhanced emission (AEE) behavior. Moreover, due to the "Jacketing" effect, the polymers showed high efficiency luminescence in the liquid crystalline state, which was significantly dependent on the spacer length (the solid-state quantum yields decreased from 52% to 18% with increasing spacer length). Meanwhile, the glass transition temperatures (T-g) decreased with increasing the length of spacers. With increasing the spacer length, the phase structure transformed from smectic A (SmA) (Pms, m = 2, 4, 6) to hexagonal columnar phase (Col(H)) (Pms, m = 8, 10, 12). All the polymers presented good film forming property and processing performance, which made them be promising materials for the luminescent devices.