Synthesis of Novel Fluorescent Conjugated Polymers and Their Rapid Gas‐Phase Detection of Trace Nitro‐Explosives.

Fluorescent conjugated polymers are widely investigated for their excellent performance in detecting explosives. In this work, two simple monomers are used to synthesize two novel fluorescent conjugated polymers, 3 and 6, with different conjugated structures via the linkages of "single bond" and "alkyne bond" by coupling reaction, and the fluorescence sensing performance for 2,4,6‐trinitrotoluene (TNT) is verified in both liquid and gas phases, aiming to demonstrate the influence of two different linkages on the fluorescence sensing properties. The fluorescent intensities of conjugated polymers in organic solvents gradually increase with increasing concentration within the low concentration range, while too high concentration leads to a decrease in the emission intensity because of the concentration quenching effect. The liquid‐phase limit of detection of 3 and 6 for TNT is as low as 1.9 and 1.6 µm in acetonitrile, respectively. The change rule of UV–vis absorption indicates that the static quenching model of TNT is predominant in liquid phase. Using a commercial portable explosives detector, 3 and 6 can effectively achieve the selective detection of gas‐phase TNT above 15 ng within 7 s and 8 ng within 5 s, respectively, demonstrating the great potential for rapid on‐site detection of trace explosives. [ABSTRACT FROM AUTHOR]