Intercalation, of water

Klinowski and coworkers were the first to undertake a study of intercalates of water (D2O) and fullerene Qq by of high resolution Solid State NMR [75]. The authors confirmed that the C60/D2O intercalate presents a dynamical system and equilibrates in a matter of hours to the 17-day stable form. MAS spectra of the Q0/D2O intercalate do not show a single resonance at 144.0 ppm, as for pure fullerene, because of the intercalated gases, and possibly perdeuter-ated water, both affecting the chemical shift. The room temperature MAS... 

Smectite clays have three important properties related to catalytic activity, intercalation, swelling and cation exchange capacity. When smectites are immersed in water, both intercalation of water molecules and swelling occur. The suspended clay can also freely exchange its interlayer cations for other cations in solution. Interlayer water molecules are dissociated producing protons and exhibit Bronsted acidity (Reaction l).8... 

LB films of tetra-4-tert-butyl- and tetra-(3-nitro-5-tcrt-butyl)-substituted CoPcs were used to detect pyridine, primary aliphatic amines, and benzylamine, by means of microgravimetry, UV-Vis spectroscopy, and optic microscopy [59], The sorption occurs as stepwise intercalation of the sorbate molecules into the supramolecular 3D structure of the phthalocyanine assembly followed by formation of the donor-acceptor complexes. Both intercalation depth and stoichiometry of the complexes are determined by the molecular structure of amines. The supramolecular factor allows discrimination between amines in air but not in aqueous solutions because of concurrent intercalation of water. 

EDS analysis after each wetting and drying cycle does not show any changes in the chemical composition. Because no cations or anions were dissolved in the water, no cation change or dissolution was possible at the temperatures employed in this study. XRD results showed an expansion of the basal spacing as a function of the relative humidity, due to the intercalation of water in the interlayers of the smectite. This effect could not be directly observed in the ESEM images. 

Possible co-intercalation of water and solvent molecules has been inferred, which may help shield the charge on the Mg " ion but can also cause severe structural distortion as well as decompose within the cathode material. Water incompatibility with the anode is another issue. 

The intercalation of water-soluble polymers is a clear case where the edge effect does not present any barrier to intercalation. An example would be the intercalation of PVP into sodium montmorillonite [1]. In this case, hydrated sodium montmorillonite as a powder can be mixed with powdered PVP in a bowl mixer and the intercalation occiurs in seconds. 

Smectite clays consist of rmits in the form of sheets or platelets , made up of two silica tetrahedral layers with a central alumina or magnesia octahedral layer. Hydrated exchangeable cations are foimd in the spaces between lattices, as shown in Fig. 13.1 (Paul and Robeson, 2008). The layers are held together by van der Waals and electrostatic forces, and the absence of primary chemical bortds allows the intercalation of water or polar organic molecitles, causing the lattice to exparrd in the c direction (Grim, 1968). 

Emulsion polymerization and suspension polymerization have been widely studied to promote intercalation of water-insoluble polymers into layered silicates such as montmorillonite, which is well known to delaminate readily in water owing to the weak forces that stack the layers together. The... 

An important property of the smectites is their ability to swell by intercalation of water or alcohols. The extent of the swelling... 

Exfoliation-adsorption in emulsion with Na -montmorillonite, known to readily delaminate clay in water has been studied to promote intercalation of water insoluble polymers. Studies by Lee et al showed that only intercalated nanocomposites were obtained in systems PMMA, PS, ° and... 

Wada, K., 1965. Intercalation of water in kaolin minerals. Am, Mineral, 50 924-941. 

The interlayer adsorption of water in the montmorillonite clays leads to interlayer or intracrystalline swelUng which is evident from the increase of the basal spacing of these expanding clays with increasing vapor pressure. The intercalation of water in these clay structures is usually limited to one to four monomolecular layers of water. The structural aspects of interlayer water adsorption are discussed in the chapters on montmorillonites and vermiculites. 

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