Structural and Optical Properties of PVA:Na2S2O3  Polymer Electrolytes Films

Omed Gh. Abdullah; Bakhtyar K. Aziz; Dler Mohammed Salh

Volume : III, Issue : XI, November - 2013

Structural and Optical Properties of PVA:Na2S2O3 Polymer Electrolytes Films

Omed Gh. Abdullah, Bakhtyar K. Aziz, Dler Mohammed Salh

Abstract :

Polymer electrolytes films based on polyvinyl alcohol (PVA) with different concentrations of Sodium thiosulphate penthydrate Na2 S2 O3 .5H2O, were prepared by solution cast technique. The optical properties in the IR and UV–visible region of PVA polymer containing 0%, 2%, 4%, 6%, and 8% by weight Na2 S2 O3 .5H2 O are investigated. The optical absorption of the prepared films increases with increasing concentration of Na2 S2 O3 .5H2 O in UV region (190–280 nm). The optical results obtained were analyzed in terms of the absorption formula for non crystalline materials. The optical band energy gap (Eg) have been obtained from direct allowed transitions in k–space at room temperature. The width of the tail of localized states in the band gap Eu was evaluated using the Urbach–edges method. It was found that both Eg and Eu, decrease as Na2 S2 O3 .5H2 O concentration increases in the polymer matrix. The optical conductance and band–gap indicated that the films are almost transmitting within the visible range. The single oscillator expression has been used to obtain the information about disorder degree. The real and imaginary parts of dielectric constant of the doped films increases with increasing Na2 S2 O3 .5H2 O concentration in the absorption edge (235–250) nm. The TGA and DTGA spectrum shows the thermal stability of polymer composite the increase with increasing Na2 S2 O3 .5H2 O content.