Liquid crystalline polymers with multicolor emission have attracted great attention in view of their great potential applications such as light-emitting diodes and information storage devices. However, luminescent liquid crystalline polymers (LLCPs) still have disadvantages involving single emission color, low solid-state emission efficiency, and poor mechanical properties. Herein, a series of main-chain LLCPs were obtained by the melt polycondensation of biobased dimethyl 2,2′-bifuran-5,5′-dicarboxylate (BFDCE), AIE-active α-cyanostilbene (Z-CS), and 1,6-hexanediol. Based on the Förster resonance energy transfer (FRET) effect between bifuran and Z-CS moieties, the emission colors of these LLCPs can be continuously tuned from blue to cyan, and then to green by changing the feed molar ratio of BFDCE and Z-CS, which can be applied in the visualization of latent fingerprints. Owing to the introduction of the rigid bifuran, the melt-pressed thin films from these main-chain LLCPs exhibit excellent tensile ductility (233%–332%), tensile strength (25.7–45.0 MPa), and medium Young's modulus (329–1028 MPa). Under 365 nm UV irradiation, the Z-CS chromophores in the main chain can undergo an irreversible [2 + 2] cyclization in the film state. Accordingly, the ‘QR code’ information and fluorescence pattern can be directly printed on the melt-pressed films instead of employing the common supporting substrates such as quartz and poly(ethylene terephthalate), paving a way for the development of anti-counterfeiting and information storage technologies.

中文翻译：

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用于生物质基主链发光液晶共聚酯的成分依赖性发射颜色，具有优异的拉伸性能


具有多色发射的液晶聚合物因其在发光二极管和信息存储设备等巨大潜在应用而受到广泛关注。然而，发光液晶聚合物 （LLCPs） 仍然存在发射颜色单一、固态发射效率低和机械性能差等缺点。在此，通过生物基二甲基 2,2′-氢呋喃-5,5′-二羧酸二甲酯 （BFDCE）、AIE 活性 α-氰基芪 （Z-CS） 和 1,6-己二醇的熔融缩聚获得了一系列主链 LLCP。基于呋喃和 Z-CS 部分之间的 Förster 共振能量转移 （FRET） 效应，这些 LLCP 的发射颜色可以通过改变 BFDCE 和 Z-CS 的馈电摩尔比从蓝色连续调整为青色，然后调整为绿色，这可以应用于潜在指纹的可视化。由于刚性呋喃烷的引入，这些主链 LLCP 的熔压薄膜表现出优异的拉伸延展性 （233%–332%）、拉伸强度 （25.7–45.0 MPa） 和中等杨氏模量 （329–1028 MPa）。在 365 nm 紫外照射下，主链中的 Z-CS 发色团在薄膜状态下可以发生不可逆的 [2 + 2] 环化。因此，“二维码”信息和荧光图案可以直接打印在熔压薄膜上，而不是使用石英和聚对苯二甲酸乙二醇酯等常见的支撑基材，为防伪和信息存储技术的发展铺平了道路。