In this research work an innovative method is used to prevent the silver ion reduction in solid polymer electrolytes. The x-ray diffraction (XRD) results reveal the disruption of the crystalline nature of chitosan (CS) and formation of silver nanoparticles upon addition of silver triflate (AgTf) salt. The UV-vis measurement confirms the existence of silver nanoparticles via the broad surface plasmon resonance (SPR) peak. Upon the addition of Al 2 O 3 nanoparticles the SPR peak intensity is greatly reduced. The amorphous domain of the CS:silver triflate (CS:AgTf) system increases with the addition of Al 2 O 3 nanoparticles up to 4 wt.%. Deconvolution of the XRD results reveals that a larger crystallite size is obtained for higher Al 2 O 3 concentrations and the peaks due to silver nanoparticles almost disappear. Scanning electron microscope (SEM) analyses show that Al 2 O 3 nanoparticles are well dispersed at low concentrations and the leakage of chains of silver nanoparticles to the membrane surface almost disappear. The XRD, UV-vis, SEM and energy-dispersive x-ray (EDX) results strongly support that the reduction of silver ions to silver nanoparticles (Ag + → Ag°) in the CS:silver triflate system is significantly avoided upon the addition of an Al 2 O 3 filler.

Chitosan : AgI solid polymer composite films have been prepared by the well-known solution cast technique. Electrical impedance spectroscopy was used to investigate the electrical percolation threshold phenomenon in this work. A wide dispersion can be seen in dielectric constant spectra at low frequencies. The dielectric constant at selected frequencies as a function of AgI concentration indicates the occurrence of electrical percolation threshold via the appearance of two distinguishable regions. The behaviour of dielectric constant and DC conductivity vs. AgI concentration are almost the same at low and high filler concentrations. The steep increase of dielectric constant and DC conductivity from 5 to 10 wt% of AgI was observed and a plateau was achieved from 10 to 20 wt% of AgI. The pattern of real part of electric modulus (M ′) at selected frequencies is similar to dielectric constant. The existence of distinct peaks in M ′′ spectra with no corresponding peaks in ε ′′ spectra indicated that ionic and polymer segmental motions are strongly coupled. Argand plots of M ′′ vs. M ′ was used to detect the relaxation type process. The Argand plots at different temperatures exhibit incomplete semicircular arc with a diameter below the real axis.

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