Solitary surfactant assisted morphology dependent chemiresistive polyaniline sensors for room temperature monitoring of low parts per million sulfur dioxide

We report the novel application of cetryltrimethylammonium bromide ( CTAB ) assisted polyaniline ( PAN ) nanostructures to fabricate cost effective chemiresistive sensors for monitoring a low parts per million level of sulfur dioxide ( SO 2 ) at room temperature. PAN nanoparticles ( NPs , diameter ca 200 nm), nanofibres ( NFs , diameter ca 100 nm) and nanoneedles ( NNs , diameter ca 50 nm) were synthesized via template‐directed chemical oxidative polymerization of aniline by varying concentration of the solitary cationic surfactant CTAB (from 5 mmol L −1 to 15 mmol L −1 ). It was observed that the PAN NN based sensing device showed an excellent sensing response ( ca 4.2%) towards a low concentration of SO 2 (10 ppm) compared to the device based on PAN NFs ( ca 3%) and PAN NPs ( ca 1.2%) at room temperature. The PAN NN based sensing device was also found to be efficient in terms of stability, selectivity, reproducibility, recovery and response time, and detection range. The mechanism of SO 2 sensing has been explored for the first time by using in situ Fourier transform infrared spectroscopy.