Thermo-electric power and humidity sensing studies of the polypyrrole/tantalum pentoxide composites

In-situ polymerization of pyrrole was carried out with tantalum pentoxide, in the presence of an oxidizing agent ammonium persulphate, in order to synthesize polypyrrole/tantalum pentoxide composites, by the chemical oxidation method. The polypyrrole/tantalum pentoxide composites were synthesized with various concentrations viz., 10, 20, 30, 40 and 50 wt% of tantalum pentoxide in pyrrole. SEM, XRD, FTIR, Thermal (TGA) and UV-Vis-NIR analyses were done on polypyrrole, polypyrrole/tantalum pentoxide composites and tantalum pentoxide. The results of See-beck coefficient, thermo-electric power factor, A.C. conductivity and dielectric properties values for the polypyrrole/tantalum pentoxide composites have demonstrated a strong dependence on the weight percent of tantalum pentoxide in the pure polypyrrole. Further, the resistance of the polypyrrole/tantalum pentoxide composites on exposure to a humid environment increases from 100 to 180 a"broken vertical bar for the composites with the increase in humidity response from 20 to 95 %.