Preparation of a functionalized glass sensor and its sensing performances for nitroaromatics

A functionalized glass sensor GS-P, which was designed for detecting nitroaromatic compounds (NACs), has been prepared by grafting conjugated polymer P on the surface of a glass slide. For control, three spin-coated films (films I, II and III) with different thicknesses were also prepared. Interestingly, the grafted polymer film showed densely packed conical columns from atomic force microscopy. Quenching efficiency study showed that polymer P exhibited 92% quench toward 2,4-dinitrotoluence (DNT) in solution state while 82% quench toward DNT vapor in film state. Quenching kinetics showed that the fluorescence intensity of GS-P decreased significantly by 80% within first the 100 s, followed by gradually decreasing to a quenching equilibrium at 200 s. This was much faster than the other two thicker films (films I and II) whose emission intensities decreased only by 37% and 48% within 100 s, respectively. The GS-P exhibited similar quenching speed as the ultra-thin spin-coated film (film III) that had the similar thickness to GS-P. Reversibility study showed that GS-P exhibited good repeatability of quenching process after the three cycles, while the ultra-thin spin-coated film hardly showed any reversibility. These great differences indicated remarkable advantages of GS-P over the spin-coated film. Furthermore, the GS-P sensor exhibited good selectivity to the NACs such as DNT, 2,4,6-trinitrotoluence, picric acid, and nitrobenzene.