Fluorescence sensing of amine vapors using a cationic conjugated polymer combined with various anions.

A series of conjugated cationic polymers, differentiated only by their accompanying counter-anions, was prepared and characterized. The choice of counter-anion (CA) was found to drastically impact the solubility of the polymers and their optical properties in solution and in the solid state. Fluorescent polymer thin films were found to be instantaneously quenched by volatile amines in the gas phase at low ppm concentrations, and a mini-array with CAs as variable elements was found to be able to differentiate amines with good fidelity.