Dielectric Dispersion and Relaxation in Polymer Blend Based Nanodielectric Film

Abstract

Summary: Polymer 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.

Preparation, Characterization and Dielectric Properties of Alginate-Based Composite Films Containing Lithium Silver Oxide Nanoparticles

“…Compared to the SA film, our composite films have a higher ε′ value. This observation is consistent with previous studies in which an increase in ε′ has been noted upon the incorporation of metal oxides into a polymer ( Prabu and Selvasekarapandian, 2012 ; Abdel-Baset et al, 2016 ; Sengwa and Choudhary, 2016 ; Choudhary and Sengwa, 2017 ). The high ε′ value of our composite films is contributed by the even dispersion of LAO NPs in the SA matrix and by the high εʹ value of LAO NPs.…”

“…The diffraction peaks from LAO NPs are found in the diffraction patterns of all of the film samples. This implies that the structure of the NPs remains unchanged, and that the films are crystalline in nature ( Afzal et al, 2008 ; Ionita et al, 2013 ; Sengwa and Choudhary, 2016 ). When the amount of LAO NPs in a film increases, the peak at 2θ = 13.32° shows a decrease in intensity but an increase in broadness.…”

“…As the temperature increases, ε′ increases. This is because an increase in temperature not only makes electric dipoles more effective in orientating themselves in the field direction ( Schildknecht and Finch, 1974 ; Hanafy, 2008 ; Masoud et al, 2013 ; Abdel-Baset et al, 2016 ) but can also result in thermal activation of the charge carriers to lead to an increase in polarization ( Sengwa and Choudhary, 2016 ). In addition, as the specific volume of the polymer increases, a small amount of the crystalline phase gets dissolved and changes into an amorphous phase, resulting in a higher ε′ value ( Rao et al, 2000 ; Awadhia et al, 2006 ).…”

Thermally improved crystalline phase and intercalated PEO/OMMT nanocomposites for high to ultrahigh radio frequency range low‐permittivity nanodielectrics

“…[1][2][3][4][5][6][7][8] Most of the studies have concluded that the nanoclay structures (i.e., the amounts of exfoliated or intercalated and the sizes of tactoids) in the host polymer matrices predominantly rule the useful properties of such hybrid nanocomposites. [1][2][3]6,[8][9][10][11][12][13] So with the consideration of this fact, enormous attempts had been made to achieve better homogeneous dispersion of loaded nanoclay platelets in the PEO matrix by adopting different preparation methods. 5,6,[9][10][11] Furthermore, numerous researches evidenced that the loading of treated-nanoclay in the polymer matrices formed highly successful nanocomposites of improved thermal and mechanical properties.…”

“…5,6,[9][10][11] In addition to the alterations in chemical and thermomechanical properties of the PNCs, it is also observed that the dielectric and electrical properties of nanoclay loaded polymer matrices are largely affected by the intercalated/exfoliated clay structures. 4,7,12,13,[16][17][18][19][20][21] However, most of the dielectric studies on the clay containing PNCs were performed with externally applied electric field starting from frequency of a few millihertz or hertz and extending up to some megahertz. It is because of the fact that the interfacial polarization largely contributes to the dielectric permittivity in all types of hybrid nanocomposites at lower frequencies which is imperative for exploring their nanodielectric applications in low-frequency device technologies.…”