Experimental investigations on nano-titania incorporated polyvinyl alcohol- polyvinyl pyrrolidone composite films

Composite films were prepared by using polyvinyl alcohol – polyvinyl acetate copolymer (PVA/Ac) blended with polyvinyl pyrrolidone (PVP) as the host polymeric material and titania (TiO2) nanoparticles (NPs) as the filler, by using ultrasonic dispersion of the filler in PVA/Ac-PVP blend solution, followed by solution casting method. Free standing films of this composite were characterized by using powder x-ray diffraction (XRD) technique, differential scanning calorimetry (DSC), thermo-gravimetric (TG) analysis, transference number determination, as well as DC and dielectric measurements. XRD patterns confirmed the incorporation of titania NPs within the polymer blend (PVA/Ac-PVP). DSC and TG techniques show that the glass transition temperature of the composite decreased, whereas its thermal stability increased on incorporating TiO2 NPs in PVA/Ac - PVP blend. Wagner’s polarization technique, which was employed to determine the transference number revealed that ions were the majority mobile charge carriers. The activation energy (Ea) has been determined from DC electrical measurements by using the Arrhenius equation; Ea was found to decrease with an increase in the filler level (FL) of titania NPs in the polymeric blend. Dielectric studies revealed maximum ionic conductivities of 7.4 × 10−5 Sm−1 and 8.63 × 10−3 S m−1 for the composite film with FL 4.90 Wt%, at temperatures 303 K and 363 K, respectively.