Fluorescence and dielectric spectroscopy identification of polyvinyl chloride/NiO nanocomposites

• Published in: Journal of molecular structure Vol. 1212; p. 128162
• Main Authors: Taha, T.A., Hendawy, N., El-Rabaie, S., Esmat, Asmaa, El-Mansy, M.K.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.07.2020
• Subjects: AC conductivity; Cole-Cole model; Dielectric constant; Fluorescence spectra; PVC nanocomposites; Cole-Cole model; Dielectric constant; PVC nanocomposites; Fluorescence spectra; AC conductivity
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2020.128162

Fluorescence spectra of the polyvinyl chloride (PVC)/NiO nanocomposites examined after excitation with wavelength of 340 nm. It revealed a visible emission peak shifted to longer wavelengths from 401.5 to 429.5 nm with the addition of 0.3 wt% of NiO nanoparticles. The dielectric properties of PVC/NiO nanocomposites also studied by broadband dielectric spectroscopy (BDS) as a function frequency (0.1 Hz - 20 MHz) at temperatures (303 – 383 K). The dielectric constant (έ) and dielectric loss (ε′′) increased with temperature but decreased with frequency. Dielectric loss peak detected at low frequency side associated with the glass-rubbery transition (α−relaxation) which shifted to higher frequencies upon increasing the temperature. The symmetric broadening shape parameter (α), average relaxation time (τo) and molecular relaxation time (τm) are calculated via the values of static (εo) and infinite (ε∞) dielectric constant estimated from Cole-Cole plots. AC conductivity followed the universal power law and enhanced with increasing both temperature and frequency owing to charge carriers hopping from one site to the others. The exponent (s) values are found to increase (0.63 – 0.9) with decreasing temperature which related to the (CBH) model. The maximum barrier height also exhibited enhancement from 0.025 to 0.027 eV with increasing the concentration of NiO, but decreased with increasing temperature. [Display omitted] •Fluorescence spectra of PVC/NiO displayed an emission peak from 401.5 to 429.5 nm.•The dielectric constant and dielectric loss increased with NiO.•The exponent (S) values are within 0.63–0.9 which related to (CBH) model.•The maximum barrier hight (Wm) values increased with NiO content.