Surface functionalization of CoFe2O4 nanoparticles for driving the crystallization of the electroactive β-PVDF through judicious tailoring of the hybrid interface

Abstract

Recently, extrinsic polymer-based magnetoelectric multiferroic materials have been investigated for many applications in nanoelectronics and energy harvesting. For that, poly(vinylidene fluoride) (PVDF), crystallized in β-phase, is known to present good ferroelectric and piezoelectric properties.We report here the functionalization of cobalt ferrite nanoparticles, known to be magnetostrictive, by a 1H,2H,2H-Perfluorooctanephosphonic acid (PFOP) for their better miscibility in PVDF. Hybrid self-standing films have been prepared; the degree of crystallinity (Xmc), as well as the fraction of β-polymorph, have been determined as a function of the amount of either functionalized or not nanoparticles, combining infrared (IR) spectroscopy and differential scanning calorimetry (DSC).We evidenced that the use of functionalized nanoparticles induced a better crystallinity degree as well as an improvement of the whole crystallization of β-PVDF polymorph. These results highlight the crucial role of the hybrid interface, when tailored through suitable surface chemistry, on the morphology developed by the hybrid.