Polypyrrole-Fe2O3 Nanocomposites with High Dielectric Constant: In Situ Chemical Polymerisation

摘要

Novel nanocomposites of polypyrrole (PPy) dispersed with iron oxide (Fe2O3) particles have been synthesised by in situ chemical oxidative polymerisation of pyrrole in the presence of ammonium persulfate (APS) as an oxidising agent. The concentration of Fe2O3 was varied between 10-50wt% of PPy. The simultaneous polymerisation of pyrrole and oxide addition led to the complete synthesis of nanocomposites. A maximum dielectric constant of similar to 28500 was observed at 20wt% of Fe2O3. The nanocomposites were characterised by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). XRD analysis confirmed the structure and crystallinity of the nanocomposites, and a strong interaction between PPy and Fe2O3 particles was observed by FTIR technique. SEM and TEM images showed that Fe2O3 particles had been coated with PPy by establishing a network during the polymerisation process. The values of dielectric constant were obtained from capacitance measurements. The value of dielectric constant for nanocomposites with 20wt% of Fe2O3 was observed to be almost 12 times that of the pure PPy matrix. The high value of dielectric constant indicated a high packing density of Fe2O3 particles in PPy matrix. These nanocomposites have potential applications in electronic or biomedical devices.