AC conductivity and dielectric characteristics of PVA/PVP nanocomposite filled with MWCNTs

• Published in: Journal of materials science. Materials in electronics Vol. 30; no. 16; pp. 15521 - 15533
• Main Authors: Abdelrazek, E. M., Abdelghany, A. M., Tarabiah, A. E., Zidan, H. M.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.08.2019; Springer Nature B.V
• Subjects: Bulk modulus; Carrier mobility; Characterization and Evaluation of Materials; Chemistry and Materials Science; Current carriers; Electrical resistivity; Equivalent circuits; Formalism; Frequency ranges; Materials Science; Multi wall carbon nanotubes; Nanocomposites; Optical and Electronic Materials; Percolation; Spectrum analysis
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-019-01929-2

AC electrical conductivity σ ac of PVA/PVP blend filled with MWCNTs was studied using impedance spectroscopy over a wide frequency range of 10 −1 to 10 7 Hz at different fixed temperatures. It was observed that the frequency-dependent nature of the ac electrical conductivity followed the Jonscher’s law and the increasing of MWCNTs content in the polymeric matrix leads to form a percolating network through the composite. On the contrary, a conductivity reduction is observed for the composition of 5 wt% of MWCNTs, which may be ascribed to the aggregation occurred in nanotubes and consequently loss of percolation. The CBH model has been suggested to agree with the conduction mechanism of σ ac for the present system. Also, the maximum barrier height over which the electrons hop decreases with increasing temperature. Impedance data were studied in terms of electrical modulus formalisms M* and impedance formalisms Z* . The relation between real and imaginary parts of complex impedance shows an inclined spike at low frequency and a semicircular arc at high frequency with radius decrease with increasing the temperature and could be best fitted to two equivalent circuit models. The analysis of M ″ and Z ″ spectra indicates that the distribution of relaxation times is independent of the temperature. The non-coincidence of peaks corresponding to M ″ and Z ″ indicates the deviation of non-Deby relaxation and short-range movement of charge carriers. The activation energy values, which are determined from the bulk conductivity and electric modulus, are very close.