In this work, side-chain luminescent liquid crystalline polymers (SCLLCPs) that contain di-substituted cyanostilbene (CS) groups with different numbers of substituted terminal alkyl chains, namely PNB-Z-4, PNB-Z-34, and PNB-Z-345, were synthesized. Their mesomorphic structure, luminescence properties and photochromic luminescent behaviour were investigated. PNB-Z-4 containing one alkyl chain in each mesogen possesses a supramolecular oblique columnar (Col_ob) phase with large lattice parameters, which can transform into a lamellar structure at high temperature. PNB-Z-34 and PNB-Z-345 with two and three alkyl tails exhibit a hexagonal columnar phase (Col_h) structure. Their fluorescence quantum yields (Φ_F) in the solid state are improved by increasing the number of alkyl tails as well. PNB-Z-34 and PNB-Z-345 exhibit aggregation-induced emission (AIE) properties, while PNB-Z-4 shows weak fluorescence. Furthermore, their photochromic fluorescence responses are quite different. PNB-Z-4 exhibits an obvious “turn-on” photo-responsive behaviour with Φ_F increasing from 0.70% to 7.73% after UV irradiation with the existence of [2 + 2] cycloaddition, while PNB-Z-34 and PNB-Z-345 show Z/E isomerization induced blueshift fluorescence response.

中文翻译：

---

含有具有不同烷基尾链数的二取代氰芪基团的侧链液晶聚合物的介晶和光致变色发光行为


在这项工作中，合成了含有二取代氰芪 （CS） 基团的侧链发光液晶聚合物 （SCLLCPs），这些基团具有不同取代末端烷基链的数量，即 PNB-Z-4、PNB-Z-34 和 PNB-Z-345。研究了它们的介体结构、发光特性和光致变色发光行为。PNB-Z-4 在每个中原中含有一条烷基链，具有具有大晶格参数的超分子斜柱状 （Col_ob） 相，在高温下可转变为层状结构。具有两个和三个烷基尾的 PNB-Z-344 和 PNB-Z-345 表现出六方柱状相 （Col_h） 结构。通过增加烷基尾的数量，它们在固态下的荧光量子产率 （Φ_F） 也得到了提高。PNB-Z-34 和 PNB-Z-345 表现出聚集诱导发射 （AIE） 特性，而 PNB-Z-4 表现出弱荧光。此外，它们的光致变色荧光响应也大不相同。PNB-Z-4 表现出明显的“开启”光响应行为，在存在 [2 + 2] 环加成反应的情况下，紫外照射后 Φ_F 从 0.70% 增加到 7.73%，而 PNB-Z-34 和 PNB-Z-345 显示 Z/E 异构化诱导的蓝移荧光反应。