Preparation of a Self-Supporting, Multilayered Film of Montmorillonite

Isayama, M.; Sakata, Kanji; Kunitake, Toyoki

doi:10.1246/cl.1993.1283

Cited by 17 publications

(7 citation statements)

References 14 publications

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“…Construction of organic−inorganic nanostructured materials is an important target of modern materials research. Formation of crystalline CdS and PbS nanoparticles under Langmuir monolayers has been studied to prepare ordered particle layers “sandwiched” by amphiphile bilayers. − A more convenient method for preparation of nanocomposite films is solvent casting of mixtures of metal oxide particles and amphiphile molecules: for example, alternate multilayers of alumina particles and amphiphile bilayers, and Li or Al double-metal hydroxide and organic acids − All these films are composed of uniformly ordered particles in two or three dimensions; however, it was not possible in the solution casting to create multilayers with precisely known numbers of layers and with predetermined alternation of different layers.…”

Section: Introductionmentioning

confidence: 99%

Alternate Assembly of Ordered Multilayers of SiO₂ and Other Nanoparticles and Polyions

et al. 1997

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Alternate layer-by-layer assembly of colloidal SiO2 particles with polycations has been investigated by quartz crystal microbalance (QCM), scanning electron microscopy (SEM), and atomic force microscopy (AFM). QCM measurement confirmed the high regularity and reproducibility of the assembling process that depends on particle concentration, particle size, and ionic strength. The individual adsorption step was completed within 15 s. The thickness of adsorbed layers increased with increasing SiO 2 concentrations at the three particle sizes used (45, 25, and 78 nm in diameter), unlike the case for other polyion assemblies. It also increased with increasing ionic strength of aqueous SiO2 dispersions. According to SEM observation, the assembled film possessed surprisingly flat surfaces at optimized ionic strengths. AFM observation revealed that SiO2 particles were not closely packed. The neutralization ratio of SiO2 and PDDA was estimated by turbidity measurement. Comparison of turbidity and QCM data indicated that the positive charge on PDDA was not completely neutralized by the negative charge on SiO2 particles in the course of alternate adsorption. This is apparently caused by a large difference in rigidity and charge density between SiO2 and PDDA. Since the charge density on PDDA is significantly larger than that on SiO2, all of the former charges cannot form short-distance ion pairs with surface charges of rigid SiO2 particles. The formation of long-distance charge pairs between SiO2 and PDDA, unlike the case for oppositely charged pairs of linear polyions, appears to be the origin of the remarkable dependence of film thickness and surface morphology on ionic strength and particle concentration. The other nanoparticles (CeO2 and TiO2) were similarly assembled with oppositely-charged linear polyions. Further modifications of the film structure were demonstrated by assembly between particles with different sizes and that between SiO2 and enzyme and by taking advantage of premixing components.

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Section: Introductionmentioning

confidence: 99%

Alternate Assembly of Ordered Multilayers of SiO₂ and Other Nanoparticles and Polyions

et al. 1997

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“…There have been reported a variety of publications on organic/inorganic ceramics (and clay) systems, − but only a few of them are devoted to production of controlled multilayers with molecular precision. Recently Kotov et al .…”

Section: Introductionmentioning

confidence: 99%

Formation of Ultrathin Multilayer and Hydrated Gel from Montmorillonite and Linear Polycations

et al. 1996

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Organized ceramic/polymer nanocomposites were designed from montmorillonite clay (Mont), cationic poly(ethylenimine) (PEI) or poly(dimethyldiallylammonium chloride) (PDDA) and proteins. Ordered multilayers with a controllable number of layers were prepared by alternate adsorption of delaminated montmorillonite (0.03 wt % dispersion) and polycations. Quartz crystal microbalance, X-ray diffraction, and scanning electron microscopy monitoring of the assembly have shown formation of ordered films with bilayer thickness of 3.3 nm for Mont/PEI and 3.6 nm for Mont /PDDA. Increased viscosity near the substrate was recognized at higher concentrations of Mont (1 wt %). At these and higher concentrations super hydrated (water content 99.4 wt %) solid gels of Mont and polycations were produced by mixing of their aqueous dispersions. Its open card-house structure was revealed with a scanning electron microscopy study.

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“…It is well-known that Na-montmorillonite can be easily dispersed and swollen in aqueous solution, and a multilayered structure can be obtained by the casting of the suspension. 16 The organic-clay hybrid materials can also be dispersed and swollen in polar organic solvents. In this experiment, dimethylformamide (DMF) was used as the solvent to act as drying control chemical additive (DCCA) for the silica gel film which prevents cracking by lowering the surface tension.…”

Section: Resultsmentioning

confidence: 99%

“…It can be seen that the organic−clay hybrid particles are dispersed as platelets of around 1 μm width in the silica matrix and are aligned almost parallel to the substrate. It is well-known that Na−montmorillonite can be easily dispersed and swollen in aqueous solution, and a multilayered structure can be obtained by the casting of the suspension …”

Section: Resultsmentioning

confidence: 99%

Dispersion and Alignment of Organic−Clay Composites within Polysilicate Thin Films by the Sol−Gel Method

1999

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Montmorillonite clay fine particles containing alkylammonium or pyridinium guests have been observed to be highly dispersed and aligned in thin films of sol-gel polysilicate networks spin-coated on quartz slide glasses. Polarized UV and visible spectroscopic analyses of the films indicate that the organic guests are aligned not only with the interlayer surfaces of the clays but also with the sol-gel polysilicate thin films. SEM and XRD observations also confirm the anisotropic disposition of the guest molecules in the composite thin films. This is in stark contrast to the case of randomly oriented clay films prepared by the casting of the suspension on slides without any matrix.

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Preparation of a Self-Supporting, Multilayered Film of Montmorillonite

Cited by 17 publications

References 14 publications

Alternate Assembly of Ordered Multilayers of SiO₂ and Other Nanoparticles and Polyions

Alternate Assembly of Ordered Multilayers of SiO₂ and Other Nanoparticles and Polyions

Formation of Ultrathin Multilayer and Hydrated Gel from Montmorillonite and Linear Polycations

Dispersion and Alignment of Organic−Clay Composites within Polysilicate Thin Films by the Sol−Gel Method

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Preparation of a Self-Supporting, Multilayered Film of Montmorillonite

Cited by 17 publications

References 14 publications

Alternate Assembly of Ordered Multilayers of SiO2 and Other Nanoparticles and Polyions

Alternate Assembly of Ordered Multilayers of SiO2 and Other Nanoparticles and Polyions

Formation of Ultrathin Multilayer and Hydrated Gel from Montmorillonite and Linear Polycations

Dispersion and Alignment of Organic−Clay Composites within Polysilicate Thin Films by the Sol−Gel Method

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Product

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Alternate Assembly of Ordered Multilayers of SiO₂ and Other Nanoparticles and Polyions

Alternate Assembly of Ordered Multilayers of SiO₂ and Other Nanoparticles and Polyions