Formaldehyde sensing properties and electrical conductivity of newly synthesized Polypyrrole-zirconium(IV)selenoiodate cation exchange nanocomposite

Abstract

Electrically conductive Polypyrrole-zirconium(IV)selenoiodate (PPy/ZSI) cation exchange nanocomposite have been synthesized by chemical oxidative polymerization of polypyrrole (PPy) in the presence of zirconium(IV)selenoiodate (ZSI) by sol-gel method. The formation of PPy/ZSI nanocomposite was characterized by fourier transform infra-red spectroscopy (FTIR), x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive x-ray (EDX) and thermogravimetric analysis (TGA). The ion exchange capacity (IEC) and electrical conductivity of the nanocomposite was found to be 2.49meq/g and 0.436S/cm respectively. The nanocomposite showed appreciable isothermal stability in terms of DC electrical conductivity retention under ambient condition up to 130°C. In addition, the cation exchange nanocomposite based sensor for detection of formaldehyde vapors was fabricated at room temperature. It was revealed that the resistivity of the nanocomposite increases on exposure to higher percent concentration of formaldehyde at room temperature (25°C), also the sensor exhibited good reversible response towards formaldehyde vapors ranging from 5 to 7%. The present study may serve as a basis for designing other smart materials for formaldehyde sensors.