Co-continuous structural polystyrene/poly(vinylidene fluoride) nanocomposites with high dielectric constant and magnetic properties

The effect of selective localization and surface modification of iron (Fe) nanoparticles on the dielectric and magnetic properties of polystyrene/poly(vinylidene fluoride) (PS/PVDF) composites with co-continuous structure was systematically studied. The carbon nanotubes (CNT) were used as co-filler with fixed content in PVDF phase to increase the dielectric properties. The modified Fe nanoparticles (p-Fe) were successfully prepared by coating the PS on the surface of Fe nanoparticles, which presented a good dispersion in the polymer matrix. The X-ray diffraction and fourier transform infrared spectroscopy results of composites show CNT and Fe/p-Fe nanoparticles have the nucleation effect on β phase of PVDF. Meanwhile, the selective localization of Fe nanoparticles in PS phase produce a high dielectric constant (ε) and the effect of selective localization of p-Fe nanoparticles in the ε is stronger than that of Fe nanoparticles and restrains the increase of dielectric loss. The composites with the selective dispersion of 4 vol% Fe nanoparticles filled in PS phase have the highest saturation magnetization than the other three. The difference of real part (μ′) of the complex magnetic permeability of the composites can be ignored and the value of μ‘ have low frequency dependence. This work could shed some light on the better optimization of such polymer composites.