Enhanced magnetoelectric coupling and dielectric constant in flexible ternary composite electrospun fibers of PVDF-HFP loaded with nanoclay and NiFe2O4 nanoparticles

Abstract

Magnetoelectric (ME) flexible nanocomposite fiber mats with a ternary composition based on the electroactive polymer poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) loaded with nanoclay (Cloisite 30B) and NiFe₂O₄ (NFO) nanoparticles have been fabricated. Different weight percentages of nickel ferrite nanoparticles were incorporated into the polymer–clay systems and their morphological, dielectric, magnetic and magnetoelectric properties have been studied. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy were used to validate the enhancement of the ferroelectric β phase of PVDF-HFP. Moreover, differential scanning calorimetric (DSC) measurements showed an improvement in the melting point of the polymer nanocomposite which also implies the enhancement of the ferroelectric β phase. The synergistic effect of the incorporation of clay and nickel ferrite nanoparticles into the PVDF-HFP matrix along with the electrospinning technique resulted in an enhancement of the electroactive nature of the polymer. The polymer nanocomposite fiber shows a magnetic saturation value of 1.54 emu g⁻¹ for the maximum loading (8 wt%) of NFO nanoparticles. The electrospun nanocomposite system with 8 wt% NFO nanoparticles exhibited the highest values of the magnetoelectric coupling coefficient (MECC) and dielectric constant (≈17 mV cm⁻¹ Oe⁻¹ and ≈29, respectively). High flexibility along with room temperature multiferroic properties makes PVDF-HFP/clay/NFO polymer nanocomposite fibers suitable candidates for device applications.