Correlation of crystal phase transition, multiferroic properties, and biotoxicity in CoFe2O4/P(VDF-TrFE) nanocomposites

Magnetoelectric (ME) nanocomposites, a novel class of functional materials, enable the conversion among magnetic, mechanical, and electrical properties. Their piezoelectric and ME properties stand out as crucial, and their biocompatibility with high ME properties remains to be verified. In this study, CoFe 2 O 4 /P(VDF-TrFE) composites with varying particle contents were prepared using the solution casting method. The microstructure of each sample was analyzed. Below 20 wt% CoFe 2 O 4 content, it is uniformly dispersed within the P(VDF-TrFE) matrix. Subsequently, the β phase content and piezoelectric properties of composites show a significant correlation. Owing to the application of a multi-needle corona polarization at 110 o C, the composites with 5 wt% CoFe 2 O 4 reached maximum values of 86.27 % and 28.4 pC/N, it also indicating that a small amount of CoFe 2 O 4 enhances the phase transformation and piezoelectric performance. In addition, the ME properties were evaluated. The maximum ME coefficient of 47.65 mV/cm·Oe was achieved with 20 wt% CoFe 2 O 4 , making it the highest value reported to date. Finite element analysis of the composites indicates that optimal ME performance depends on the composites possessing both good ferroelectric and ferromagnetic properties. The biotoxicity experimental results demonstrate that all the samples which treated in an 80 o C water bath exhibit excellent biocompatibility.