Polybenzimidazole derivative and application in field of fluorescent probes

The invention discloses a polybenzimidazole derivative and application in the field of fluorescent probes. According to the invention, trans-butenedioic acid is taken as a bridge, novel conjugated polybenzimidazole with a large conjugated nano-microsphere structure is synthesized, and insoluble conjugated polybenzimidazole is modified through N-alkylation reaction, so that the nano-microsphere polybenzimidazole derivative with good solubility and optical performance is successfully obtained; the polymer is adjustable in fluorescence, can be used as a multifunctional fluorescent probe for simultaneously detecting Cu and Zn, can also be used as a turn-off type fluorescent probe for simultaneously detecting various metal ions, and has a relatively low detection limit; and the modified polymer can be used for manufacturing test paper and thin-layer chromatography plates for detecting Cu, achieves rapid detection is achieved, and can also be designed into a molecular-level ultra-sensitive implication g