Multifunctional (PVP/PEO)/SnO2 nanocomposites of tunable optical and dielectric properties

Polymer nanocomposites (PNCs) are technologically established as multifunctional advanced materials particularly for flexible-type electronic components and devices. For the progress on PNCs, in this work, tin oxide (SnO2) nanoparticles as nanofiller up to 5 wt% contents and a host matrix of equal compositional ratio of poly(vinyl pyrrolidone) (PVP) blended with poly(ethylene oxide) (PEO) were taken for the preparation of PNC films through casting of aqueous solutions. The SEM micrographs of these films revealed noticeable changes in the macrosized spherulites and microsized pores of the polymer matrix on initial dispersion of 1 wt% SnO2 nanoparticles and further 3 wt% and 5 wt%. The FTIR results evidenced that the SnO2 nanoparticles mainly behaved as geometrical incarceration for the blended polymer structures due to which the contents of PEO crystallites anomalously changed as revealed from their XRD results. The UV-Vis absorbance study of these materials confirmed a non-linear increase of absorbance in the UV-region and decrease of energy band gap when the SnO2 content increased gradually. These materials exhibited SnO2 concentration dependent dielectric permittivity and electrical conductivity in the frequency window of 20 Hz to 1 MHz. Dominant effect of interfacial polarization in dielectric spectra at low frequencies and the relaxation process of these hybrid materials are explained. The experimental results suggest multifunctionality of these biodegradable PNC materials as UV-shielders, optical band gap tuner, and dielectric permittivity and conductivity controllable nanodielectrics.