Investigation of structural, thermal and dielectric properties of polypyrrole nanotubes tailoring with silver nanoparticles

Polypyrrole nanotube-silver nanoparticles nanocomposites (PPy-NTs/Ag-NPs) have been synthesized by in situ chemical reduction of silver nitrate (AgNO3) by sodium borohydride (NaBH4) in the presence of pre-synthesized polypyrrole nanotubes (PPy-NTs) by varying the silver concentration. The nanocomposites have been investigated by HRTEM, SEM, XRD, TGA, UV-vis spectroscopy, impedance analyzer and I-V characteristics for their structural, thermal, optical, dielectric and electrical properties. The average diameter of PPy-NTs and silver nanoparticles (Ag-NPs) has been determined to be 130 and 25 nm, respectively. The thermal stability of the nanocomposites is enhanced, which may be attributed to suppression of the degradation of polypyrrole due to dispersion of silver nanoparticles. The enhanced dielectric properties of nanocomposites may be attributed to the interfacial space charge polarization. Significant increase in the ac conductivity of the nanocomposites is attributed to the extra contribution of conductivity from interfacial capacitive regions.