Although it is well-known that nitroaromatic compounds quench the fluorescence of
different conjugated polymers and form colored Meisenheimer complexes with proper nucleophiles,
the potential of paper as a substrate for those macromolecules can be further developed. This work
undertakes this task, impregnating paper strips with a fluorene-phenylene copolymer with quaternary
ammonium groups, a bisfluorene-based cationic polyelectrolyte, and poly(2-(dimethylamino)ethyl
methacrylate) (polyDMAEMA). Cationic groups make the aforementioned polyfluorenes attachable
to paper, whose surface possesses a slightly negative charge and avoid interference from cationic
quenchers. While conjugated polymers had their fluorescence quenched with nitroaromatic vapors
in a non-selective way, polyDMAEMA-coated papers had a visual response that was selective to
2,4,6-trinitrotoluene (TNT), and that could be easily identified, and even quantified, under natural
light. Far from implying that polyfluorenes should be ruled out, it must be taken into account that
TNT-filled mines emit vapors from 2,4-dinitrotoluene (DNT) and dinitrobenzene isomers, which
are more volatile than TNT itself. Atmospheres with only 790 ppbv TNT or 277 ppbv DNT were
enough to trigger a distinguishable response, although the requirement for certain exposure times is
an important limitation.
