Tetrahedral rehydration during imogolite formation

Wilson, Michael; Lee, Garry S. H.; Taylor, Renee C.

doi:10.1016/s0022-3093(01)00908-5

Cited by 32 publications

(50 citation statements)

References 46 publications

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“…The presence and intensity of XRD peaks of this nanotube are close related to the condition of sample 35,36 . The shape and intensity of the first peak (at 20 nm) are always related to the external diameter and the tubular structure characteristic peaks (d = 2.00, 0.90, 0.63 and 0.39 nm), are assigned to (010), (020), (030), and (032), respectively 4 (see Figure 3, right).…”

Section: Introductionmentioning

confidence: 56%

“…Figure 3 shows other IR imogolite absorption signals located at 428, 506, 577, and 967 cm -1 ; in addition, close to 3500 cm -1 a band associated to -OH stretching can be observed. In general terms, imogolite IR spectra are more acute tan theses of allophane being the doublet at 577 and 967 cm -1 the most significant difference (see Figure 3, left) 12,34,35 .…”

Section: Introductionmentioning

confidence: 95%

“…identification uncertainty related to the presence of imogolite because during aging process proto-imogolite is formed which is hard to differentiate from imogolite through IR and XRD, signals considering that both aluminosilicates have the same functional groups and similar crystalline ordering 11,12,35 .…”

Section: Introductionmentioning

confidence: 99%

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Nanotubular Aluminosilicates: A Case Study for Science and Industry

Arancibia‐Miranda¹,

Lillo²,

Escudey³

2013

J. Chil. Chem. Soc.

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The renewed interest in imogolite nanotubes, with structural similarities with carbon nanotubes (CNTs), has led to a new search of the potential of imogolite in the field of nanoscience. The applications of imogolite started being studied at the beginning of the 1970s, but the lack of technological development prevented a detailed study of this aluminosilicate. Furthermore, the strong incursion CNTs, which show exceptional structural characteristics and physical properties, left imogolite as the subject of secondary studies and applications in nanotechnology. This review, revise the scientific interest on imogolite from its discovery until the present, showing the main areas of research and development for this nanotube from a nanotechnological point of view.

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Section: Introductionmentioning

confidence: 56%

Section: Introductionmentioning

confidence: 95%

See 1 more Smart Citation

Nanotubular Aluminosilicates: A Case Study for Science and Industry

Arancibia‐Miranda¹,

Lillo²,

Escudey³

2013

J. Chil. Chem. Soc.

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“…Transmission electron microscopy (TEM) is often used to characterize the morphology of synthetic imogolite [5][6][7][8][9] . Typically TEM specimen is prepared by depositing a drop of imogolite solution on a film-coated copper grid and drying in air.…”

Section: Synthetic Imogolite Nanotubes Droplet Evaporation Individmentioning

confidence: 99%

“…The SiOH groups are located on the inner surface of the nanotube, while AlOH groups are on the outer surface. The hydroxyl groups on the walls and rims make the nanotube hydrophilic [1][2][3][4] .Transmission electron microscopy (TEM) is often used to characterize the morphology of synthetic imogolite [5][6][7][8][9] . Typically TEM specimen is prepared by depositing a drop of imogolite solution on a film-coated copper grid and drying in air.…”

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confidence: 99%

Individual dispersion of synthetic imogolite nanotubes via droplet evaporation

Yang

2007

CHINESE SCI BULL

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Morphology of synthetic imogolite nanotubes formed in droplet evaporation was investigated by transmission electron microscopy and electron diffraction. The nanotubes form a dense entangled network at higher concentrations, while at lower concentrations the nanotubes are liable to form oriented bundles. Under enthanol atmosphere, individual dispersion of nanotubes was observed for the first time, which reveals the length polydispersity of synthetic imogolite nanotubes. synthetic imogolite, nanotubes, droplet evaporation, individual dispersionImogolite is a naturally occurring aluminosilicate found mainly in weathered volcanic ash, and can also be synthesized from dilute solutions of hydroxyaluminium orthosilicate. Natural imogolite has an external tube diameter of ca. 2 nm and an internal diameter of ca. 1 nm. The lengths of natural nanotubes are in the order of a few microns. The chemical composition of imogolite is (OH) 3 Al 2 O 3 SiOH. The SiOH groups are located on the inner surface of the nanotube, while AlOH groups are on the outer surface. The hydroxyl groups on the walls and rims make the nanotube hydrophilic [1][2][3][4] .Transmission electron microscopy (TEM) is often used to characterize the morphology of synthetic imogolite [5][6][7][8][9] . Typically TEM specimen is prepared by depositing a drop of imogolite solution on a film-coated copper grid and drying in air. A random network of nanotubes is the most common morphology, and the tubular structure has been observed [5] . The periodic repeat unit along the nanotube axis is also revealed by corresponding electron diffraction (ED) patterns.The investigation on the dimensions of imogolite nanotubes avails to understanding the structure evolution and formation mechanism in the synthesis process. Polydispersity in lengths of natural imogolite nanotubes was proposed based on mathematical analysis of small angle X-ray scattering (SAXS) or light scattering data [10] , while for synthetic imogolite, Nair et al. [3] reported a monodisperse nanotube length of 100 nm in solution determined by dynamic light scattering. However, direct observation of individual imogolite nanotubes by TEM has not been available because of redistribution and aggregation of the nanotubes during the droplet drying process when the specimen is prepared.Here we report the morphology of synthetic imogolite nanotubes observed by controlling surface effects in droplet evaporation. In particular, individual dispersion of imogolite nanotubes was observed for the first time.We synthesized imogolite by the method of Farmer et al. [11] and the resulting solution was dialyzed against distilled water to remove unreacted silicic acid, monomeric aluminum, and NaCl. A drop of dialyzed solution was deposited onto a carbon-coated Formvar copper grid and dried at room temperature. The specimen was observed using a JEOL 1011 transmission electron microscope operated at 100 kV. The camera length was calibrated with Au standard.

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Nonclassical Growth Mechanism of Double‐Walled Metal‐Oxide Nanotubes Implying Transient Single‐Walled Structures

Paineau,

Bourdelle,

Bhandary

et al. 2024

Small

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The formation of imogolite nanotubes is reported to be a kinetic process involving intermediate roof‐tile nanostructures. Here, the structural evolution occurring during the synthesis of aluminogermanate double‐walled imogolite nanotubes is in situ monitored, thanks to an instrumented autoclave allowing the control of the temperature, the continuous measurement of pH and pressure, and the regular sampling of gas and solution. Chemical analyses confirm the completion of the precursor's conversion with the release of CO2, ethanol, and dioxane as main side products. The combination of microscopic observations, infrared, and absorption spectroscopies with small and wide‐angle X‐ray scattering experiments unravel a unique growth mechanism implying transient single‐walled nanotubes instead of the self‐assembly of stacked proto‐imogolite tiles. The growth formation of these transient nanotubes is followed at the molecular level by Quick‐X‐ray absoprtion specotrscopy experiments. Multivariate data analysis evidences that the near neighboring atomic environment of Ge evolves from monotonous to a more complex one as the reaction progresses. The following transformation into a double‐walled nanotube takes place at a nearly constant mean radius, as demonstrated by the simulation of X‐ray scattering diagrams. Overall, transient nanotubes appear to serve for the anchoring of a new wall, corresponding to a mechanism radically different from that proposed in the literature.

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Tetrahedral rehydration during imogolite formation

Cited by 32 publications

References 46 publications

Nanotubular Aluminosilicates: A Case Study for Science and Industry

Nanotubular Aluminosilicates: A Case Study for Science and Industry

Individual dispersion of synthetic imogolite nanotubes via droplet evaporation

Nonclassical Growth Mechanism of Double‐Walled Metal‐Oxide Nanotubes Implying Transient Single‐Walled Structures

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