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Polymer-based zinc oxide/titanium dioxide (ZnO/TiO2) nanocomposites flexible sheets with high dielectric permittivity and low loss factor have numerous applications in light emitting and energy storage devices. In this work, polymer-based ZnO/TiO2 nanocomposites are synthesized by co-precipitation technique and their structural, morphological, elemental composition, dielectric and electrical properties are studied. The XRD analysis shows the development of diffraction planes related to TiO2 and ZnO phases confirming the synthesis of polycrystalline polymer-based ZnO/TiO2 nanocomposites. The crystallinity of various phases is associated with increasing ZnO nanofillers. The SEM analysis reveals the formation of nanoparticles of different shapes and dimensions associated with increasing amount of ZnO nanofillers. The EDX analysis confirms the presence of Zn, O and Ti in the synthesized nanocomposites. Dielectric measurements demonstrate the sharp increase in dielectric permittivity with relatively low dissipation factor of the nanocomposites. The observed AC conductivity of the nanocomposites at 3.0 × 105 and 1.0 × 106 Hz is ranged from 3.7–9.8 and 15.6–42.7 S/m respectively. The decreasing complex impedance and increasing electric modulus further confirm that the synthesized polymer-based ZnO/TiO2 nanocomposites flexible sheets are the promising candidates for better capacitive performance showing high strength and flexibility. [ABSTRACT FROM AUTHOR]

This study demonstrates the remarkable improvement in structural, optical and dielectric properties of flexible sheets of polymer-based zinc oxide nanocomposites (PB-ZnO-NCs) synthesized by co-precipitation method. The X-ray diffraction patterns show the development of ZnO (100), ZnO (002), ZnO (101) and ZnO (102) diffraction peaks. The variation in peak intensities and crystallite sizes are associated with increasing wt.% of ZnO nanofillers. The FTIR analysis confirms the presence of vibrational modes of PVDF, ZnO and O-H groups and shows strong bonding between PVDF and ZnO, when ZnO is more than 20wt.%. The SEM microstructural analysis of polymer is appeared just like microfibers which is changed into cloudy microstructure when 10 wt.% ZnO nanofillers are mixed, however, the surface morphology strongly depends on increasing wt.% of ZnO nanofillers. The small shift in absorption edges and increasing values of absorption for PVDF and ZnO depend on the increasing wt.% of ZnO nanofillers. The values of energy band gap are found in the range from 5.69-5.47 eV and 3.65-3.38 eV for PVDF and ZnO respectively. Dielectric measurements demonstrate a sharp increase in dielectric permittivity with relatively low loss factor. The static value of dielectric constant at 100 Hz is found to be 13.88 for sample having 50 wt.% ZnO nanofillers which is 4.2 times greater than PVDF and shows relatively low value of loss factor. The observed AC conductivity of synthesized PB-ZnO-NCs having 50 wt.% ZnO and 50 wt.% PVDF is found to be 2.16×10-5 S/m which is 3.2 times larger than PVDF at 1×106 Hz. Results indicate that a chain of polymer matrix arises due to defects and capsulated microstructures, increased with increasing wt.% of ZnO nanofillers which make the NCs more flexible, strengthen and conductive. [ABSTRACT FROM AUTHOR]

Flexible dielectric polymer nanocomposites (NCs) with high dielectric permittivity and low loss factor have numerous applications in light emitting and storage devices. In this research work, polymer based NCs in the form of flexible sheets containing 5% ZnO and 15, 20% SiO2 nano-fillers, are synthesized by using co-precipitation method. X-ray diffraction analysis reveals the development of various diffraction planes related to ZnO and SiO2 phases confirms the synthesis of polycrystalline PB–ZnO–SiO2 NCs flexible sheets corresponding to various compositions. Morphology and compositional analysis show the uniform distribution of nanoparticles in polymer matrix with estimated elemental contents in each composition. Dielectric measurements demonstrate a sharp increase in dielectric permittivity with relatively low dissipation factor in synthesized compositions having ZnO and SiO2 nano-fillers. The static value of dielectric constant at 100 Hz is found to be 10.79 for sample having 20% SiO2 nano-fillers that is 3.4 times greater than pure PVA and it shows relatively low value of dissipation factor. The observed AC conductivity of synthesized NCs flexible sheets having 5% ZnO, 20% SiO2 nano-fillers is 2.15 × 10–5 S/m that is 3.3 times greater than pure PVA at 1 × 106 Hz. Complex impedance spectroscopy further confirms, these materials as promising candidates for better capacitive performance. [ABSTRACT FROM AUTHOR]