Polymer-assisted synthesis of metallopolymer nanocomposites and their applications in liquefied petroleum gas sensing at room temperature

In this paper, the synthesis of the acrylamide complex of Co (II) nitrate followed by polymerization and formation of a polymer composite with inclusions of Co nanoparticles stabilized by the polymer matrix has been reported. Cobalt polyacrylamide (Co/PAAM) was prepared by the procedure including formation of cobalt acrylamide complex, followed by frontal polymerization and pyrolysis of the polymer. Structural investigations of the materials were carried out by X-ray diffractometer. Surface morphologies were analyzed using scanning electron microscope and nano-structural properties were studied by using high resolution transmission electron microscope and atomic force microscope. Phase transformation temperature was evaluated using a differential scanning calorimeter. The crystallite size of the Co/PAAM was found ∼6 nm and confirmed by TEM analysis. Thick films of the metallopolymers were made by screen printing technique and these were investigated with exposition of LPG for measurements of LPG sensing characteristics. Larger variations in resistance were found for Co/PAAM in comparison to Co(NO3)2·(AAM)4·2H2O. The maximum values of the sensitivities were 2.9 and 23.6 MΩ/s for Co(NO3)2·(AAM)4·2H2O and Co/polyacrylamide respectively. The reproducibility of the sensor made of Co/PAAM film was found to be 96% after one month of observations, which shows the stability and reliability of the fabricated sensor.