Plasma-Polymerized and Iodine-Doped Polyvinyl Acetate for Volatile Organic Compound Gas Sensing Applications

Nowadays, the increased emission of hazardous volatile organic compounds (VOCs) due to rapid growth in the manufacturing industry has enforced demand for highly sensitive, selective, and stable gas sensors. Among the different types of gas sensors, we resolved issues associated with chemoresistive alcohol sensors like low selectivity, temperature instability, and long-term instability using iodine-doped polyvinyl acetate (IPVAc) films. These polymer-based chemoresistive sensors will be beneficial for low power consumption, ease of manufacture, and long-term stability owing to their simple structure and operation. The polymer films were prepared using the inductively coupled tubular plasma polymerization method. These films were doped with iodine at room temperature. The physicochemical characterization of prepared films confirmed the uniform coating of granular type morphology, iodine doping, and cubical crystal structure. The obtained maximum sensitivity was 122 and 7360 a.u. for 1000 ppm of methanol gas for polyvinyl acetate (PVAc) and IPVAc films, respectively. Also, IPVAc films demonstrated sensitivities of 5554 and 1995 a.u. for 1000 ppm of each ethanol and 2-propanol gas, respectively. IPVAc films illustrated the highest selectivity of 600 a.u. for alcohols over other VOCs like acetone, benzene, toluene, and dichloromethane. The high electronegativity of IPVAc films due to iodine doping is the key origin of the highly selective adsorption of VOCs. Additionally, the IPVAc films have stable sensitivity performance over the temperature range of 30-130 degrees C and repeatability over 60 days. Thus, the plasma-polymerized IPVAc films can be applied for fabricating highly selective, sensitive, and stable VOC sensing applications.