Cross-linked polymer phosphorescence fibers based on chitosan and corresponding wet-spinning processing

Organic room-temperature phosphorescence (RTP) material is a new kind of triplet emission material, which shows great advantages in applications. How to realize the green preparation and processing of this kind of material attracted increasing attention, while the related works were still rare. In this work, a natural polymer of chitosan was selected as the rigid matrix to construct RTP materials, while aromatic carboxylic derivatives were introduced as phosphor guests, and citric acid was employed as a crosslinking agent to enhance phosphorescence intensity, lifetime and structural stability. Through a simple and environmentally friendly amidation reaction, the crosslinked RTP polymers with blue-green-red emissions were successfully prepared. Further on, a green wet-spinning processing was utilized to optimize the alignment of polymer chains, significantly improving RTP performance with the achievement of the phosphorescence lifetime up to 1.58 s in chitosan-based filaments. In addition, filaments with excitation-dependent RTP property were successfully prepared with a similar method, which exhibited dynamic color changes across the visible region as the excitation wavelength changed. These unique properties highlight their potential for applications requiring dynamic, long-lived luminescence.

有机室温磷光（room-temperature phosphorescence, RTP）材料是一类新型三重态发射材料，在诸多应用场景中展现出突出优势。如何实现该类材料的绿色制备与加工愈发受到关注，但相关研究仍较为匮乏。本研究选取天然高分子壳聚糖作为刚性基质以构建RTP材料，同时引入芳香族羧酸衍生物作为磷光客体，并以柠檬酸作为交联剂，用以提升磷光强度、延长磷光寿命并增强结构稳定性。通过简单且环境友好的酰胺化反应，我们成功制备出兼具蓝、绿、红三色发射特性的交联型RTP聚合物。在此基础上，我们采用绿色湿纺工艺优化聚合物链的排列取向，显著提升了RTP性能，所制备的壳聚糖基纤维丝的磷光寿命最高可达1.58秒。此外，通过相似方法我们还成功制备出具备激发依赖型RTP特性的纤维丝，其磷光颜色可随激发波长的变化在可见光区域内呈现动态色彩变化。这些独特的性能凸显了该材料在需要动态、长余辉发光的应用场景中的应用潜力。