Correlation between Crystallization Kinetics and Electroactive Polymer Phase Nucleation in Ferrite/Poly(vinylidene fluoride) Magnetoelectric Nanocomposites

Abstract

Poly(vinylidene fluoride) (PVDF) nanocomposites with different ferrite nanoparticle loadings are interesting as, depending on ferrite type and content, the electroactive β-phase of the polymer is nucleated and the magnetoelectric coupling is induced. The isothermal crystallization behavior of ferrite/PVDF nanocomposites is studied using polarized optical microscopy, and the crystallization kinetic is analyzed by the Avrami theory in order to understand the crystallization conditions leading to the nucleation of the electroactive polymer phase. It is found that the nucleation kinetics is enhanced by the presence of ferrite nanoparticles, as evidenced by the increasing number of spherulites with increasing nanoparticle content and by the variations of the Avrami exponent. The crystallization velocity is intimately related to the polymer α- or β-phase formation in the nanocomposites and follows the order NiFe(2)O(4)/PVDF > CoFe(2)O(4)/PVDF > Ni(0.5)Zn(0.5)Fe(2)O(4)/PVDF for a given temperature and nanoparticle loading, which results in larger amounts of β-phase for CoFe(2)O(4)/PVDF and Ni(0.5)Zn(0.5)Fe(2)O(4)/PVDF nanocomposites.

Effect of ionic liquid anion and cation on the physico-chemical properties of poly(vinylidene fluoride)/ionic liquid blends

“…This decrease of the spherulite size is attributed to the strong electrostatic interactions of the IL with the polymer chains, which show strong local dipole moments [26,27]. It is proven that strongly interactive fillers within the PVDF polymer matrix, not only act as nucleation centers for crystallization, but also modify the crystallization kinetic, leading to smaller spherulites [28]. The reduction of the average size of the spherulites thus dependent on the ion type present in the IL structure.…”

Development of magnetoelectric CoFe2O4 /poly(vinylidene fluoride) microspheres

“…Ceramicbased ME materials exhibit ME coefficients three orders of magnitude higher than polymer-based ME materials, but they are limited by reactions at the interface regions which lead to high dielectric losses, hindering sustainable device applications 1 . Thus, polymer-based ME materials have attracted increasing interest from the industry since they solve the abovementioned application problems 1,11 . Further, in polymer-based ME materials strain coupling does not deteriorate with operation, as the magnetostrictive material is in direct contact with and completely surrounded by the piezoelectric polymer matrix, they show simple and scalable production methods, a flexible structure without large leakage currents, can be fabricated by conventional low-temperature polymer processing into a variety of forms, such as thin sheets or molded shapes, can exhibit tailored mechanical properties, flexibility, lightweight, versatility, low cost and in biocompatibility 1, 2 .…”

“…In this work the development of novel CoFe 2 O 4 (CFO)/polyvinylidene fluoride (PVDF) multiferroic spheres is reported, with large potential applications in the biomedical, sensing, actuation, catalysis and energy fields [13][14][15] . PVDF, a piezoelectric polymer with five possible distinct crystalline phases named as α, β-phase, γ, δ and ɛ, was selected as the piezoelectric component due to its biocompatibility, high piezoelectric response, large chemical and radiation resistance, easy shaping and low cost 11,[22][23][24] . CFO nanoparticles were selected as the magnetostrictive phase due to their chemical stability, mechanical hardness, wear resistance, ease of synthesis, large magnetostriction, high Curie temperature, low cost and simple processability 25,26 .…”

Enhanced electroactive and mechanical properties of poly(vinylidene fluoride) by controlling crystallization and interfacial interactions with low loading polydopamine coated BaTiO 3

“…8d [39]. In other word, the higher DE of PVDF/BT-Pdop would be more favorable for the nucleation of the PVDF b-phase [40].…”