Formation of oriented iron oxide particles in cast multibilayer films

Okada, Hideo; Sakata, Kanji; Kunitake, Toyoki

doi:10.1021/cm00008a001

Cited by 50 publications

(24 citation statements)

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“…Of these, only the last two offer the ability to introduce periodic microstructural and compositional changes needed for nanocomposite assembly. With regard to nanolaminated structures, supramolecular self-assembly has resulted in the formation of lamellar (silica/surfactant) films 12 multi-bilayer composite films 13 , but such non-covalently bonded structures are mechanically unstable unless pillared 14 (for example, lamellar silica-surfactant coatings collapse to amorphous silica on surfactant removal 12 ). Sequential deposition has been used to prepare stable inorganic/organic nanocomposites 11 , but this process requires many repeated deposition steps to build up a practical coating thickness.…”

mentioning

confidence: 99%

Continuous self-assembly of organic–inorganic nanocomposite coatings that mimic nacre

Sellinger

Weiss

Nguyen

et al. 1998

Nature

564

430

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Nanocomposite materials are widespread in biological systems. Perhaps the most studied is the nacre of abalone shell, an orientated coating composed of alternating layers of aragonite (CaCO 3 ) and a biopolymer. Its laminated structure simultaneously provides strength, hardness and toughness: containing about 1 vol. % polymer, nacre is twice as hard and 1,000 times as tough as its constituent phases 1 . Such remarkable properties have inspired chemists and materials scientists to develop synthetic, 'biomimetic' nanocomposite assemblies 2-5 . Nonetheless, the efficient processing of layered organic-inorganic composites remains an elusive goal. Here we report a rapid, efficient selfassembly process for preparing nanolaminated coatings that mimic the structure of nacre. Beginning with a solution of silica, surfactant and organic monomers, we rely on evaporation during dip-coating to induce the formation of micelles and partitioning of the organic constituents into the micellar interiors 6 . Subsequent self-assembly of the silica-surfactant-monomer micellar species into lyotropic mesophases 7 simultaneously organizes the organic and inorganic precursors into the desired nanolaminated form. Polymerization fixes this structure, completing the nanocomposite assembly process. This approach may be generalized both to other composite architectures and to other materials combinations.Natural nanocomposites are formed by biomineralization 5 , a templated self-assembly process in which pre-organized organic surfaces regulate the nucleation, growth, morphology and orientation of inorganic crystals. Related synthetic, so-called 'biomimetic', approaches include crystallization beneath Langmuir monolayers 8 , crystallization on self-assembled monolayers 3,9 , supramolecular self-assembly 2,6,10 and sequential deposition 11 . Of these, only the last two offer the ability to introduce periodic microstructural and compositional changes needed for nanocomposite assembly. With regard to nanolaminated structures, supramolecular self-assembly has resulted in the formation of lamellar (silica/surfactant) films 12 or letters to nature 256

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mentioning

confidence: 99%

Continuous self-assembly of organic–inorganic nanocomposite coatings that mimic nacre

Sellinger

Weiss

Nguyen

et al. 1998

Nature

564

430

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“…The composite films displayed larger coercivity and magnetic anisotropy. It has been reported that the magnetic anisotropy of the composite films could be achieved by ordered orientation of magnetite particles in an ordered multibilayer film (Okada et al 1990). The magnetic anisotropy of the composite films would be resulted from the regular distribution of the Fe 2 O 3 nanoparticles in the composite films, also the magnetic crystalline anisotropy of the plate-like Fe 2 O 3 nanoparticles contributed to the magnetic anisotropy properties of composite films.…”

Section: Resultsmentioning

confidence: 99%

In situ synthesis of plate-like Fe2O3 nanoparticles in porous cellulose films with obvious magnetic anisotropy

2011

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Nanocomposite cellulose films with obvious magnetic anisotropy have been prepared by in situ synthesis of plate-like Fe 2 O 3 nanoparticles in the cellulose matrix. The influence of the concentrations of FeCl 2 and FeCl 3 solutions on the morphology and particle size of the synthesized Fe 2 O 3 nanoparticles as well as on the properties of the composite films has been investigated. The Fe 2 O 3 nanoparticles synthesized in the cellulose matrix was c-Fe 2 O 3 , and its morphology was plate-like with size about 48 nm and thickness about 9 nm, which was totally different from those reported works. The concentration of FeCl 2 and FeCl 3 solution has little influence on the particle size and morphology of the Fe 2 O 3 nanoparticles, while the content of Fe 2 O 3 nanoparticles increased with the increase of the concentration of the precursor solution, indicating that porous structured cellulose matrix could modulate the growth of inorganic nanoparticles. The unique morphology of the Fe 2 O 3 nanoparticles endowed the composite films with obvious magnetic anisotropy, which would expand the applications of the cellulose based nanomaterials.

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“…Kunitake and coworkers reported that the magnetic anisotropy of composite film could be achieved by ordered orientation of magnetite particles in an ordered multibilayer film. [39] Magnetic anisotropy of the cellulose Synthesis and Alignment of Iron Oxide Nanoparticles . .…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Alignment of Iron Oxide Nanoparticles in a Regenerated Cellulose Film

Liu

Zhou

Zhang

et al. 2006

Macromol. Rapid Commun.

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Summary: A polymer‐iron oxide nanocomposite film has been successfully synthesized by using a microporous regenerated cellulose film as template and aqueous ferrous chloride as precursor. The nanocomposite film was investigated with XRD, XPS, SEM, TEM, and VSM. The nanoparticles synthesized in situ were disk‐shaped with a mean diameter of ≈24 and thicknesses of 2.5–3.5 nm. For the first time, the nanodisks were well aligned in the cellulose matrix to form an ordered multibilayer structure by the shrinkage of the hybrid film while drying. The nanocomposite film displayed anisotropic magnetic properties as a result of the alignment of magnetic nanodisks. This work provides a novel and facile method for template synthesis of nanoparticles and aligned nanocomposites.TEM image of the air‐dried nanocomposite film; slice perpendicular to the film plane.magnified imageTEM image of the air‐dried nanocomposite film; slice perpendicular to the film plane.

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Formation of oriented iron oxide particles in cast multibilayer films

Cited by 50 publications

References 1 publication

Continuous self-assembly of organic–inorganic nanocomposite coatings that mimic nacre

Continuous self-assembly of organic–inorganic nanocomposite coatings that mimic nacre

In situ synthesis of plate-like Fe2O3 nanoparticles in porous cellulose films with obvious magnetic anisotropy

Synthesis and Alignment of Iron Oxide Nanoparticles in a Regenerated Cellulose Film

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