Dielectric and AC Conductivity Studies in PPy-Ag Nanocomposites

K Praveenkumar,R Ramanna,J S Ashwajeet,T Sankarappa

doi:10.1155/2015/893148

Abstract

Polypyrrole and silver nanoparticles have been synthesized at 277 K by chemical route. Nanoparticles of polypyrrole-silver (PPy-Ag) composites were prepared by mixing polypyrrole and silver nanoparticles in different weight percentages. Dielectric properties as a function of temperature in the range from 300 K to 550 K and frequency in the range from 50 Hz to 1 MHz have been measured. Dielectric constant decreased with increase in frequency and temperature. Dielectric loss decreased with increase in frequency and increased with increase in temperature. Using dielectric data AC conductivity has been determined. Conductivity was found to be in the order of 10−3 (Ω−1 m−1) and it increased with increase in temperature. Temperature variation of conductivity data has been analyzed in the light of Mott’s polaron hopping model. Activation energy for conduction has been determined. Activation energy was determined to be in the order of meV and it has increased with increase in frequency and Ag nanoparticles content. This is the first time that PPy-Ag nanocomposites have been investigated for dielectric properties and AC conductivity and data analyzed thoroughly.

Highlights

Polypyrrole (PPy) and silver (Ag) are two different types of conductors
The composites made of a metal and an organic semiconductor are expected to exhibit a good level of conductivity as well as tunable physical and chemical properties [7]
Pure analytical grade pyrrole, ammonium peroxidisulphate, methanol, acetone, silver nitrate, and sodium borohydride were used in the preparation of PPy nanoparticles and silver nanoparticles

Summary

Introduction

Polypyrrole (PPy) and silver (Ag) are two different types of conductors. PPy is an organic polymer exhibiting semiconductivity and Ag is a metal. The properties of metal nanoparticles and conducting polymers instigated an interest in many researchers to synthesis and study nanocomposite materials [1,2,3,4,5,6]. Synthesis and size control of PPy nanoparticles have been studied and reported that PPy nanoparticles can be effectively dispersed due to large surface area and they exhibit good conductivity [8,9,10]. There are not many research reports on PPy-Ag composites studied for dielectric and AC conductivity properties as a function of temperature and frequency over wide ranges. In this communication, we present dielectric studies carried out on PPy-Ag nanocomposites. Conductivity data has been analyzed in the light of Mott’s small polaron hopping model [16]

Experimental

Results and Discussions

Conclusions