The role of TiO2 nanoparticles in enhancing the structural, optical, and electrical properties of PVA/PVP/CMC ternary polymer blend: nanocomposites for capacitive energy storage

Abstract

Herein, titanium dioxide (TiO2) nanoparticles (NPs) were prepared via the sol–gel technique; then, they were incorporated into a ternary blend polymer matrix to design polymer nanocomposite (PNC) films through the solution casting technique. The ternary blend polymer matrix consisted of polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), and carboxymethyl cellulose (CMC). X-ray diffraction (XRD) analysis revealed reductions in the crystallinity structure of the polymer matrix after adding TiO2 NPs. The optical study manifested increases in the refractive index and reduction in the optical bandgap values, which reduced from 4.97 eV for the pure polymer blend to 4.77 eV for the PNC film at TiO2 content of 3 wt%. Additionally, the transmission edge gradually shifted towards lower energy. The PNC films exhibited considerable improvements in the dielectric constant (ε′), dielectric loss (ε′′), dielectric moduli (M′ and M′′), and electrical conductivity characteristics over the range of frequency range from 0.1 Hz to 10 MHz. The addition of TiO2 NPs improved the electrical conductivity and dielectric constant significantly. The electrical conductivity increased by over ten times compared to the pure ternary polymer blend, and ε′ also rose four-fold at 100 Hz. The enhancement in the electrical and dielectric parameters of the PNC films after adding TiO2 nanofiller could indicate the suitability of these samples for flexible-type energy storage applications, such as dielectric capacitors. Graphical Abstract: [Figure not available: see fulltext.]