Facile synthesis of an electrically conductive polycarbazole-zirconium(IV)phosphate cation exchange nanocomposite and its room temperature ammonia sensing performance

In this study, we reported the synthesis of an electrically conductive polycarbazole-zirconium(IV)phosphate (PCz-ZrP) cation exchange nanocomposite as a new sensing material. Zirconium(IV)phosphate (ZrP) assisted in situ chemical oxidative polymerization of carbazole was used for the synthesis of PCz-ZrP. Field emission scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis and X-ray diffraction analysis were applied to characterize the PCz-ZrP cation exchange nanocomposite. Strong interactions between the inorganic particles (ZrP) and organic polymer (PCz) were observed. Thermogravimetric analysis revealed that the PCz-ZrP nanocomposite had higher thermal stability than pure PCz. Moreover, the composite showed good ion-exchange capacity, electrical conductivity and isothermal stability in terms of DC electrical conductivity retention under ambient conditions below 100°C. A nanocomposite based sensor was fabricated for sensing aqueous ammonia at room temperature. An increase in resistivity on exposure to ammonia at room temperature was observed with a direct relationship between response and ammonia concentration. The PCz-ZrP nanocomposite-based sensor showed a quick and reversible response towards aqueous ammonia.