Polymer matrix templated synthesis: Cobalt ferrite nanoparticles preparation

Abstract

Cobalt ferrite (CoFe2O4) nanoparticles were successfully synthesized by polymer matrix templated synthesis. Synthetic ion-exchange resins were used as hosts for the coprecipitation of cobalt ferrite where the nanopores of the resin acted as the constrained environment. The weight fraction of the particles within the resin was roughly 16%. X-ray diffraction analysis indicated that cobalt ferrite crystallites were about 1–7 nm in diameter. Magnetic properties measured using an alternating gradient magnetometer showed the particles (prepared using initial salt solution ratio of Fe3+:Co2+ of 1.5:1.0) were superparamagnetic with magnetization M (of the particle-resin system) in the range of 3.0 to 4.4 emu/g at 10 kOe of applied field. The least upper bound of the magnetic size was about 3 nm in diameter. Ratios of Fe3+ to Co2+ within the matrix of the resin before and after precipitation were investigated by x-ray fluorescence spectrometry and were found to be sensitive to the initial salt solution mixture. The ratio Fe3+:Co2+ of 1.5:1.0 was found to be a better mixture in terms of magnetization value. Spherical shape cobalt ferrite particles 2–8 nm in diameter were observed using transmission electron microscopy. The close agreement between the physical and crystallite size indicated that the particles are largely monocrystals.

Preparation and characterization of polyvinyl alcohol–cobalt ferrite nanocomposites

“…In agreement with similar works [5,8] the addition of NaOH initiates the precipitation process of products particles within the polymer matrix. The heating process transforms the precipitated precursors into magnetic oxide.…”

Poly(styrene–b–ethylene/butylene–b–styrene)/cobalt ferrite magnetic nanocomposites

“…These particular peak positions and d spacings indicate that the metal oxide phase was the inverse spinel CoFe 2 O 4 , and these results were close to data reported in other articles. 15,[19][20][21][22][23][24] Oxides such as maghemite, cobalt ferrite, and so forth (generally of the type MO.Fe 2 O 3 , cubic) and barium ferrite (MO.6Fe 2 O 3 , hexagonal) are ferrimagnets. 14…”

“…[21][22][23] The effect of the Fe(III):Co(II) ratio in an sPS matrix has been studied. 24 Cobalt ferrites can also be formed in an amorphous silica matrix. 15 Here, we report the preparation and characterization of magnetic nanocomposites that were created by the precipitation of CoFe 2 O 4 nanoparticles in sulfonated SEBS templates.…”

Synthesis of CoFe2O4 nanowire arrays by sol–gel template method

“…Among the family of ferrite materials, cobalt ferrites, used in video tape and high-density digital recording, are the most commercially significant particulate recording materials. Cobalt ferrite particles [6][7][8][9][10] and films [11][12][13] have attracted the interests on the exploration of recording materials. …”