Synthesis of a novel fluorene-based conjugated polymer with pendent bulky caged adamantane moieties and its application in the detection of trace DNT explosives

A novel fluorene-based conjugated polymer with phenylene spacers and steric bulky adamantane moieties in side chains has been synthesized by palladium-catalyzed Suzuki coupling reactions. This design strategy offers several advantages for the detection of trace 2,4-dinitrotoluene (DNT) vapor. The incorporation of the two groups into polymer side chains could retain an effective conjugation length and prevent the π-stacking of polymer chains. The detection of DNT vapor indicated that the polymer displayed higher fluorescence quenching sensitivity toward the explosives in films compared to reference polymers. The fluorescence quenching efficiency of the fluorescent polymer achieved 33.3% in 10 s and 71.1% in 60 s. The pathways or cavities generated by the two spacers are beneficial for the rapid diffusion of explosive vapor into the film interiors and increase the fluorescence quenching efficiency of the film.