Effect of PEG nanoparticle surface coating on the magnetic and structural properties of CoFe2O4/PVDF composites

Abstract

This research focuses on the impact of polyethylene glycol (PEG) coating on the magnetic and structural properties of composites consisting of an electroactive polyvinylidene fluoride matrix and CoFe2O4 nanoparticles. The intrinsic piezoelectric and magnetic properties of the constituents fundamentally determine the properties of composites, but the microstructure and particle packing of the composite are equally crucial for enhancing magnetoelectric coupling. Our findings reveal that PEG coating promote a more uniform spatial distribution of particles agglomerates within the polymer matrix, which achieved by strengthening of the interfacial coupling and reducing of the filler density during the solvent casting process. Together with reduced agglomerates size from an average of 28 ± 3 μm to 17 ± 1 μm uniform spatial distribution leads to decrease of magnetic dipolar interactions from ∼ 900 Oe to ∼ 800 Oe - tendence confirmed from the first-order reversal curve (FORC) analysis. Additionally, the root mean square roughness of the composite surface decreases from 185 nm to 74 nm, indirectly confirming increased sample uniformity. Local electrical properties, measured through Piezoresponse Force Microscopy (PFM), show a substantial enhance of the local piezoelectric response by ∼ 40 %. Results can be used for the enhancing of magnetoelectric effect in biocompatible materials, utilized at low frequency.