Synthesis, optical, and electrical properties of starch/chitosan/NaTiO₃ bio-nanocomposites modified with ErCl₃

Abstract

Solid polymer electrolytes (SPEs) based on nanocomposites are attracting increasing attention due to their technological and industrial applications. In the present work, a facile aqueous casting method was utilized for the preparation of a starch-chitosan blend loaded with nanosized NaTiO3 (NTO) and co-mixed with ErCl3 (EC) salt. The interactions between OH group of starch and N–H group of chitosan with NTO and EC, and the films' crystallinity and surface morphology were studied by FTIR, XRD, and SEM. UV-Vis-NIR measurements showed the indirect (direct) optical band gaps decreased from 3.4 to 2.0 eV (4.5 to ~ 2.5 eV), i.e., ~ 41–44 % shrinking. At the time that the films maintained a reasonable transmittance. The optical constants of the films; extinction coefficient, refractive index, and the carrier’s concentration to the electron effective mass (N/m*) are reported. N/m* of the pure blend was 4.85 x 1039 (kg-1 m-3) increased to 1.64 times and 2.8 times after loading with 1.0% NTO and 20% EC, respectively. Various dielectric parameters (dielectric constant ε', dielectric loss ε'', ac conductivity σac, and dielectric moduli M' & M'') were evaluated in the frequency range 5 Hz - 1 MHz and temperatures of 298 - 353 K. The conductivity (σac) of the blend increased from 1.10×10-3 S/cm to 8.17×10-3 S/cm after modifying with 20% EC, i.e., became 8 times greater. Moreover, the influence of NTO and EC on the conduction mechanism and Cole-Cole plots are discussed. The improvements in the optical and electrical properties of EC/NTO/blend illustrate the possibility of extending the applications of these smart materials to include optoelectronic devices, batteries, and supercapacitors.

Synthesis, structural, optical and electrical characterization of Y2O3/poly(ethylene glycol)–poly(vinyl chloride) based nanocomposite solid polymer electrolytes

“…As is known, FWHM equals 1.14 for Debye relaxation and >1.14 for non‐Debye relaxation 58 . Similar behavior was reported in other polymeric systems 29,51 …”

“…The semicircles visible in Fig. 13 are a common feature in most polymeric systems 29,51 . As is obvious, increasing T decreases the radii of the semicircles, which reflects the promotion of ionic conductivity 26 .…”

“…Dielectric measurements were performed to see if the produced NCSPE films might be used as solid polymer electrolytes. In addition, these measurements are helpful in studying other electrical phenomena, such as relaxation behavior, polarization and charge transport mechanisms 26–29 …”

“…In order to reduce the polarization effects of the electrodes and to discuss in depth the dielectric relaxation phenomena in the prepared films, the electric modulus formalism was used 29,50,51 . The real and imaginary parts of the modulus spectra, M′ and M″ , are depicted in Figs S5 and 12, respectively, for the films as a function of ω at different T .…”

“…In addition, these measurements are helpful in studying other electrical phenomena, such as relaxation behavior, polarization and charge transport mechanisms. [26][27][28][29] Dielectric constant and dielectric loss investigation The dependence of the dielectric constant ε 0 on the frequency (f ) and temperature (T) for the prepared films is shown in Fig. 9.…”