Sensor performance and computational study of polyaniline film in ethylenediamine detection

The incorporation of computational chemistry toward the assessment of polyaniline (PAni) performance as ethylenediamine (EDA) sensor is first explored in this study. Through chemical oxidative polymerization, PAni is synthesized at different temperatures and applied as chemical sensor for EDA detection. PAni(0°C) exhibits higher electrical conductivity (1.486 × 10−2S/cm) and better sensitivity (0.0529) with R2 of 0.8419 compared to PAni(25°C). The presence of branches in PAni(25°C) hinders EDA from approaching the reactive sites of PAni and hence resulted in low sensitivity of 0.0022. Besides, 0.5 ppm limit of detection was obtained by using 3 layers of PAni(0°C). PAni(0°C) showed good recyclability of up to 10 cycles with 7 s short response time and 5 s fast recovery time. Meanwhile, good recoveries of 110% and 95% were obtained for real sample analysis for PAni(0°C). The high electrical conductivity of PAni(0°C) is supported by its low band gap energy of −0.2803 eV that was obtained by computational data. Based on the computational data, PAni(0°C) possesses the highest sensitivity in EDA detection with the short response time of 7 s which shows good agreement with the high interaction energy of 294 kcal/mol. Thus, a simple and effective EDA sensor is successfully developed. Highlights PAni(0°C & 25°C) were successfully characterized by FTIR and UV–Vis analysis. PAni(0°C) shows higher conductivity due to formation of longer polymer chain. Higher sensitivity toward EDA (slope = 0.0529) is obtained for PAni(0°C). PAni(0°C) tetramer shows higher interaction energy and lower band gap energy. PAni(0°C) shows 7 s response time, 5 s recovery time, and up to 10 recycling cycle. Interaction mechanism and optimization of PAni (0°C and 25°C) towards EDA detection.