ac impedance, DSC and FT-IR investigations on (x)PVAc-(1-x)PVdF blends with LiClO4

The blended polymer electrolytes comprising poly(vinyl acetate) (PVAc)-poly(vinylidene fluoride) (PVdF) have been prepared for different blend composition with constant lithium perchlorate (LiClO4) ratio by solution casting technique. The formation of the blend polymer electrolyte complex has been confirmed by Fr-IR spectroscopy analysis. DSC analysis has been performed in order to observe the change in transition temperature that is caused by the blending of polymers and addition of LiClO4. The ac impedance and dielectric spectroscopy studies are carried out on the blended matrix to identify the optimized blend composition, which is having high ionic conductivity. The temperature dependence of conductivity of the polymer electrolytes is found to follow VTF type equation. The high ionic conductivity of 6.4 x 10(-4) S cm(-1), at 343 K has been observed for blended polymer electrolyte having blend ratio 75:25 (PVAc:PVdF). The ionic transference number of mobile ions has been estimated by Wagner's polarization method and the value is reported to be t(ion) is 0.95-0.98 for all the blended samples. The modulus spectra reveal the non-Debye nature and distribution of relaxation times of the samples. The dielectric spectra show the low frequency dispersion, which implies the space charge effects arising from the electrodes. (c) 2005 Elsevier B.V. All rights reserved.