Binary doped polypyrrole and polypyrrole/boron nitride nanocomposites: preparation, characterization and application in detection of liquefied petroleum gas leaks

We report an electrical conductivity based rapid response liquefied petroleum gas (LPG) sensor using binary doped polypyrrole and polypyrrole/boron nitride (PPy/BN) nanocomposites as the conductive material. Binary doped PPy and PPy/BN nanocomposites have been synthesized using a chemical oxidative in situ polymerization method using FeCl3 as an oxidant in the presence of camphorsulfonic acid (CSA). A PPy/BN nanocomposite has also been synthesized using a chemical oxidative in situ polymerization method using FeCl3 as an oxidant. PPy/FeCl3/CSA, PPy/BN/FeCl3 and PPy/BN/FeCl3/CSA were characterized using Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis and field emission scanning electron microscopy. On the basis of these results, the well-organized structural nanocomposites were successfully prepared owing to specific interactions between the PPy and the BN nanosheets. The results indicated that the morphology and electrical properties of the nanocomposites were significantly influenced by the BN nanosheet loading and CSA. Transformation of non-conducting PPy/BN/FeCl3 into conducting PPy/BN/FeCl3/CSA was also observed. Addition of CSA caused a significant increment in electrical conductivity due to binary doping of the nanocomposites. The as-prepared PPy/FeCl3/CSA and PPy/BN/FeCl3/CSA nanocomposites were studied for the change in their electrical conductivity on exposure to liquefied petroleum gas (LPG) and ambient air at room temperature with the possible use as a sensor for detection of LPG leaks.