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