Improved electroactive phase content and dielectric properties of flexible PVDF nanocomposite films filled with Au- and Cu-doped graphene oxide hybrid nanofiller

In the present work, new and flexible poly(vinylidene fluoride) (PVDF) based nanocomposites containing Au- and Cu-doped graphene oxide (GO/Au and GO/Cu) nanosheets were prepared by solution casting. The resulting nanocomposites present a high content of electroactive phases and high dielectric constant accompanied with low dielectric loss which make them interesting for possible applications in sensors and electronic devices. Fourier transformed infrared spectroscopy (FTIR) was used to study the crystalline structure of nanocomposites which showed no absorption band related to non-polar a phase. FTIR confirmed an enhancement of the electroactive phase with the increase in nanofiller concentration due to the electrostatic interactions among the CH2-CF2 dipoles of PVDF and nanofiller. Electroactive phase content as calculated from FTIR spectra presented a maximum value of about 95% for PVDF filled with 1% GO/Au nanofiller. This value is about 2.5 times higher than that of neat PVDF. For a given filler concentration, nanocomposites filled with GO/Au showed a higher increase of electroactive phase in comparison with those containing GO/Cu. This trend was also confirmed by X-ray diffraction (XRD) spectra. From inductance, capacitance, and resistance (LCR) measurement, nanocomposites display high dielectric constant, increasing with the nanofiller content, and low dielectric loss which is favorable to fabricate flexible and simple high performance nanodielectric materials.