Structural and Electrical Properties of PVA/PVP Blend Doped with Methylene Blue Dye

Films of PVA/PVP blend (1:1) doped with different levels of methylene blue dye (MB) were prepared using the casting technique. X-ray, IR, DC and AC analyses were used to give more information about structural variation that arises due to different doping levels. Semi-crystalline nature of PVA/PVP blend revealed from X-ray diffraction pattern. The crystallinity of the doped blends decays as the doping level of MB increases. The IR analysis showed that a presence of double bond segments which are assumed as an appropriate sites for polarons and/or bipolarons. The dependence of the DC electrical conduction on the temperature was ascribed in view of phonon-assisted interpolaron one-dimensional hopping of charge carriers. Dielectric analysis showed that the values of epsilon(r) decrease with increasing frequency and becomes constant at higher frequencies. On the other hand, epsilon(r) increases with the temperature. The sigma(ac) values increase with increasing the frequency as well as MB content. The values of the frequency exponent S designate that quantum mechanical tunneling mechanism (QMT) is the dominant model within prepared samples.