Dielectric Dispersion and Relaxation in Polymer Blend Based Nanodielectric Film

Abstract

SummaryPolymer nanodielectrics is the exponential growing field of advanced materials sciences. Such flexible materials have recognized their suitability as substrate and insulator in fabrication of microelectronic devices, and also in preparation of ion conducting solid polymer electrolytes. The nanodielectric film consisted of poly(ethylene oxide) and poly(methyl methacrylate) (PEO–PMMA; 75/25 wt/wt%) blend with 5 wt% montmorillonite (MMT) clay as nanofiller has been prepared by solution‐casting method followed by melt‐pressed technique. The X‐ray diffraction study of the film confirms the intercalated MMT structures in the semicrystalline phase of PEO–PMMA blend. The scanning electron microscopic images confirm the significant variation in morphology of the PEO–PMMA blend on addition of MMT nanofiller. The dielectric relaxation spectroscopy has been employed for measurement of complex dielectric function, ac electrical conductivity and electric modulus spectra of the nanodielectric film in the frequency range 20 Hz–1 MHz. The value of real part of dielectric function of the film is found high at low frequencies due to contribution of electrode polarization effect, but it decreases non‐linearly with the increase of frequency and finally approaches the high frequency limiting value of 2.3 at 1 MHz. The relaxation peak in dielectric loss spectra corresponding to polymer segmental motion is found above 10 kHz, and the peak positions have a shift towards higher frequency side with the increase of temperature. The dc conductivity increases and the relaxation time of the polymer segmental motion decreases with increasing temperature of the nanodielectric film according to the Arrhenius behaviour.