Dodecyl benzene sulfonic acid (DBSA) doped polypyrrole (PPy) films: synthesis, structural, morphological, gas sensing and impedance study

摘要

Chemical oxidative polymerization of PPy using APS as an oxidizing agent and mechanical blending were utilized to fabricate PPy-DBSA nanocomposites. DBSA plays a role as both dopant and surfactant in the process of nanocomposite synthesis. In this paper, PPy-DBSA nanocomposites are prepared in m-cresol solvent and deposited on glass substrate with various concentrations of DBSA (10-50 Wt%). It is confirmed using X-ray diffraction analysis and Raman spectroscopy that DBSA actually interacts with the PPy matrix and structural formation of PPy-DBSA nanocomposites. The surface morphology of PPy doped with DBSA (PPy-DBSA) is observed with field emission scanning electron microscopy and atomic force microscopy. The compositional analysis carried by energy dispersive photoelectron spectroscopy and X-ray photoelectron spectroscopy evidenced the successful formation of PPy-DBSA nanocomposite. The 10 % PPy-DBSA nanocomposite sensors are selective and sensitive towards NO_2 gas so gas response measured at low concentration range of 5-100 ppm. The sensor shows high stability, good reproducibility and recovery time for NO_2 gas. The gas sensing mechanism is proposed schematically and is confirmed using impedance analysis.