Cellulose-based fluorescent film probes for the recognition and removal of Hg2+/Hg+ ions

The improved solubility of cellulose, and the enlargement of its application is of importance. Herein, we have synthesized cellulose probes with aggregation-induced emission (AIE) effect, which demonstrates high efficiency and sensitivity in detecting Hg2+ /Hg+ ions. The cellulose underwent esterification with a 11‑carbon chain using pyridine as both catalyst and reaction medium, leading to break off H bonds and a significant decrease in crystallinity. This modification allowed the cellulose to be soluble in dichloromethane (DCM) and toluene. Additionally, long-chain oil-soluble BODIPY fluorescent polymers were synthesized using 2-(dimethylamino) ethyl methacrylate (DMAEMA) as monomer via BODIPY containing RAFT reagent. The oil-soluble BODIPY fluorescent polymers were connected to cellulose through the Heck reaction, leading to the preparation of cellulose fluorescent probes. These probes could be easily dissolved in strong polar organic solvents like N, N-dimethylformamide (DMF) and ethanol, but also in DCM and toluene. They can be made into films and gels. Furthermore, the probe utilizes BODIPY as the fluorophore and CO as the binding recognition site for Hg2+ and Hg+. The detection limits are 50 nM and 60 nM, respectively. The cellulose solubility was improved, and the cellulose based probes could be employed to detect and separate Hg2+ and Hg+. [Display omitted] •Cellulose derivatives could be easily dissolved in common solvent.•Long polymers as side chains contribute a lot to improve the solubility.•The fluorescent cellulose-based probes could be made into films and hydrogels.•The probes can recognize and separate Hg2+/ Hg+ through AIE effect.