Enhanced dielectric properties of poly(vinylidene fluoride) matrix nanocomposites incorporated with one–dimensional structure of titanate nanotubes

Abstract

The dielectric properties of polymer nanocomposites based on a poly(vinylidene fluoride) (PVDF) matrix, filled with a one–dimensional nanostructure of titanate nanotubes (TNTs), were investigated. These studies demonstrated significant improvements in the energy storage capability of the application. The TNTs were synthesized through an alkali hydrothermal treatment method at 130 °C for 24 h, using a 10 M NaOH solution. The TNTs exhibited a large dielectric permittivity of approximately 1.2 × 104 with a low loss tangent of approximately 0.12 at 1 kHz and 25 °C. TNTs/PVDF polymer nanocomposites were studied and fabricated using liquid phase–assisted dispersion and hot–pressing methods. By introducing TNTs into the PVDF polymer, both the dielectric permittivity and loss tangent increased. Notably, the polymer nanocomposite containing 50 wt. % TNTs exhibited a dielectric permittivity of 5.3 × 103 at 1 kHz, which is ∼530 times greater than that of pure PVDF (10.78), while the loss tangent remained at 0.572. The low–frequency dielectric permittivity increased with an increase in relative humidity from 50 to 95 % due to enhanced interfacial polarization at the surface and electrode interface. However, at frequencies greater than 1 kHz, the dielectric permittivity was independent of relative humidity. The improvement in the enhanced dielectric permittivity of polymer–based nanocomposites with incorporated TNTs was ascribed to these factors.