Effect of toluene-4-sulfonic acid monohydrate concentrations on properties of polyaniline for pyrene detection via photoluminescence spectroscopy

Detection of pyrene as a toxic chemical is vital to possess a healthy, non-polluted and well sustainable environment. Toluene-4-sulfonic acid monohydrate (PTSA) doped Polyaniline in emeraldine salt (PANI) as a suitable material can be used to develop a new sensing material for pyrene detection. The relative amounts of PANI and PTSA are still an important aspect to realize the optimum combination. In this study, PANI and different concentrations of PTSA doped PANI were prepared using chemical polymerization of the monomer's aniline in acid environments at room temperature. UV–visible spectroscopy (UV–vis), Fourier transform infrared light (FT-IR), field emission scanning electron microscopy (FE-SEM), electrical analysis, and photoluminescence spectroscopy (PL) were applied to determine bandgap values, physical and structural properties, morphology patterns, electrical conductivity, and fluorescence intensity respectively. The high conductivity value was obtained in 1% PTSA doped PANI with the value of 27 × 10−1 (Ω cm)−1 due to decreasing the bandgap value. Also, 1% PTSA doped PANI demonstrates high PL intensity owing to its orderly organized benzenoid and quinoid parts. Particularly, 1% PTSA doped PANI was selected as a suitable candidate for pyrene detection with a linear range of 0.001–10 ppm and a limit of detection of 7 × 10−3 ppm. This work provides a facile method to prepare a novel sensing material for the detection of pyrene with high sensitivity and fast response.