A novel film of conjugated polymer grafted onto gelatin for detecting nitroaromatics vapor with excellent inhibiting photobleaching

A novel sensing material (Gel-P) based on conjugated carbazole polymer grafted onto gelatin was successfully synthesized by spin-coating way. The grafting reaction between gelatin and Polymer P was confirmed by ATR-FTIR spectra of Polymer P and the content of residual amino group in gelatin solution. After UV irradiation for 30 min, the fluorescence intensity of Gel-P only reduced by 7.6%, while the polystyrene film doped with polymer P (Ps + P) decreased by 32.4%, indicating higher capability in inhibiting photobleaching for Gel-P due to the presence of tryptophan in gelatin and the fixation effect of gelatin molecules to polymer chains via hydrogen bonds between amino and hydroxyl. Exposed to saturated DNT vapor, the Gel-P sensor exhibited a high quenching efficiency (Qf) of 60% after 50 s and the fluorescence of P in Gel-P film was completely quenched for 300 s owing to the plenty of NH2 and OH groups in gelatin, which could effectively absorb nitroaromatics (NACs) by hydrogen bonding interaction between NACs and gelatin. After being exposed to saturated DNT vapor for 300 s, the Gel-P sensor showed good reversibility of quenching process.

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