Composites of Poly(3,4-ethylenedioxythiophene) and CoFe₂O₄ Nanoparticles: Composition Influence on Structural, Electrical, and Magnetic Properties

Abstract

Composites of magnetic CoFe 2 O 4 nanoparticles (MNP) in a Poly (3,4-ethylenedioxythiophene) matrix at different ratios have been synthetized. Composites were characterized by electron microscopy, X-ray diffraction, thermal analysis, electrical conductivity, magnetization and magnetoresistance studies. In the composites the MNP appear clustered, with an interparticle distance essentially constant, but where two regimes are distinguished for cluster separation: for high MNP concentrations an intercluster separation similar to the interparticle distance is found, while for low MNP contents the distance between clusters is larger than the interparticle separation. The electrical conductivity increases with polymer content, but being always far lower than general effective medium theory expectations. This indicates that the effect of MNP effect on polymer conduction is probably related to the generation of mechanical stress by both introducing additional scattering centers and by producing different arrangement of the polymer chains, compared with the pure PEDOT. The magnetization studies reveal the existence of the RKKY interaction, which couples ferromagnetically the MNP located in a cluster, while the dipolar interaction dominates the interaction between clusters. Magnetoresistance was studied for these composites, with a maximum value close to 0.7% at 0.8 T for the lowest polymer content.The magnetoresistance correlates very well with the reversible part of the magnetization, indicating that its possible origin should be associated with polymer mechanical deformation due to the magnetic-field-induced rotation of the MNP.

Spin Disorder and Particle Size Effects in Cobalt Ferrite Nanoparticles with Unidirectional Anisotropy and Permanent Magnet-like Characteristics

“…A comparison of literature reports with the magnetic parameters of our calcined CoFe 2 O 4 demonstrates the efficacy of our approach (Table S2). ,,,,− ,,,− …”

Tuning the electrical and magnetic properties in multifunctional composite materials based on the PEDOT:DBS conducting polymer and magnetite nanoparticles

“…These hybrid composites are part of a new generation of smart materials, 18 and those based on PEDOT have been proposed for applications in catalysis, magnetic field sensors, microwave absorption, ion adsorption, and antibacterial agents, among others. 19–23…”

“…There are few works that report the influence of the composite composition on the physicochemical properties of these materials. 19,22,24–27 For example, Ohlan et al 22 synthesized and characterized PEDOT-barium ferrite nanocomposites with different compositions. They found that these materials have strong microwave absorption properties, which depend on the barium ferrite concentration in the polymer matrix, and a shielding effectiveness that increases with the ferrite content.…”

Surface modification of Ag–CdO with polyaniline for the treatment of 3′,3″,5′,5″-tetrabromophenolsulfonphthalein (BPB) under UV-visible light irradiation

“…Some of these contaminants are pharmaceuticals, personal care products, pesticides, disinfection by-products, and synthetic chemicals such as dyes [ 3 ]. The list is ever-expanding due to an advanced instruments to detect contaminants in water bodies and by-product formed during wastewater treatment processes [ 4 ] in the concentrations range of μg/L to ng/L [ 5 ]. Organic dyes are non-biodegradable, highly toxic to aquatic organism, and carcinogenic to humans.…”