Electrospun magnetoactive hybrid P(VDF-TrFE) scaffolds heavily loaded with citric-acid-modified magnetite nanoparticles

The development of magnetoactive scaffolds based on piezoelectric polymers is of great interest due to their ability to exert a magnetoelectric effect, their flexibility, and biocompatibility in various prospective applications. This study describes fabrication of novel electrospun magnetoactive scaffolds based on poly(vinylidene fluoride-co-trifluoroethylene) [P(VDF-TrFE)] loaded with a high content (20 or 25 wt%) of magnetite nanoparticles modified by citric acid (Fe₃O₄-CA) and data on their structure and physicochemical, mechanical, and magnetic properties as well as a piezoelectric response. The suspension method gave a uniform nanoparticles' distribution in the electrospun scaffolds without any noticeable agglomeration. Raman and infrared spectroscopy and X-ray diffraction analysis indicated that the fabricated pure scaffolds and composite P(VDF-TrFE)/Fe₃O₄-CA scaffolds contain both piezoactive phases (β and γ). The composite scaffolds doped with 20 or 25 wt% of Fe₃O₄-CA nanoparticles were found to have the highest saturation magnetization, 12.7 and 14.1 emu/g, respectively, superior to that of other PVDF-Fe₃O₄–based magnetoactive scaffolds. Besides, the incorporation of 20 or 25 wt% of Fe₃O₄-CA nanoparticles substantially decreased total crystallinity of the piezopolymer scaffolds from 60.7% to 46.9% and 42.7%, respectively. Addition of 20 wt% of Fe₃O₄-CA nanoparticles also diminished ultimate strength and Young's modulus but improved elongation at break. Meanwhile, in composite P(VDF-TrFE)/Fe₃O₄-CA scaffolds loaded with 20 wt% of the magnetic filler, the piezoresponse was similar to that of pure P(VDF-TrFE) scaffolds. Such changes in properties are explained by the interaction between P(VDF-TrFE) polymer chains and the surface of Fe₃O₄-CA nanoparticles via hydrogen bonds and dipolar bonds.