Temperature dependent studies of electric and dielectric properties of polythiophene based nano composite

摘要

The fabrication, characterization, electric, dielectric and ac conductivity measurement of polythiophene and carbon nanotube (CNT) composite are described. The polythiophene (PTh) and polythiophene/ multiwalled carbon nanotube (PTh/MWCNT) composite are prepared chemically by oxidative polymerization of thiophene(Th). The formation of PThand incorporation of CNTs into PTh are confirmed by Fourier Transform – Infrared spectroscopy (FT-IR) and Energy Dispersive X-Ray analysis (EDAX) analysis. Scanning Electron Microscopic (SEM) analysis revealed the formation of polymer/CNT composite. SEM image of PTh shows a leaf like structure and image of PTh/MWCNT shows the incorporation of MWCNT into the PTh flakes. Atomic force microscopic (AFM) analysis shows the morphology of PTH and PTh/MWCNT. The structural features of Nanotube-Polymer association are observed by AFM studies. The electrical behaviour of prepared samples has been studied by measuring I-V characteristics at varying temperature. The dielectric properties of these samples have been studied at low frequencies (150-700 kHz) for varying temperature. The dielectric constant for PTh/MWCNT is found to be higher than PTh for all temperature ranges. Finally,theac electrical conductivity (σac) and dielectric relaxation time calculations have been carried out by using the data available from dielectric measurements and by employing a simple relationship. Conductivity shows a linear dependence on temperature and is also higher for PTh/MWCNT.