Micas thermodynamic properties

Table 5.57 Thermodynamic properties of mica end-members in databases of Helgeson et al. (1978) (1), Saxena et al. (1993) (2), Berman (1988) (3), and Holland Powell (1990) (4). =...

Massoime, HJ Szpmka, Z (1997) Thermodynamic properties of white micas on the basis of high-pressure experiments in the systems K20-Mg0-Al203-Si02-H20 and K20-Fe0-Al203-Si02-H20. Lithos 41 229-250... 

However, these physicochemical investigations were to a substantial extent approximate and incomplete, due to the lack of thermodynamic constants of many rock-forming minerals (amphiboles, micas, chlorites, etc.) to imprecision in the tabulated calculated constants (siderite, ferrosilite, fayalite, etc.) to the substantial discrepancies between theoretical and experimental equilibrium data and to the lack of data on the properties of the fluid at high pressures. Moreover, many thermodynamic calculations were made by approximate methods, which led to substantial errors. 

Surfactant molecules are made up of two moieties that have antagonistic properties, a polar or electrically charged hydrophilic moiety and a hydrophobic moiety, most often an alkyl chain. In aqueous solution, most surfactants self-assemble and form micelles when their concentration becomes larger than the so-called critical micellization concentration (CMC). In micelles (fromthe Creek mica, which means "grain "), the alkyl chains are in contact and form an oily core that is coated by the polar head groups. The outer layer that contains head groups, counterions (in the case of ionic surfactants), water and the first methylene group of the alkyl chain is called the palisade layer. The formation o/micelles is a cooperative process that is spontaneous and reversible. Micelles are thermodynamically stable species that are in chemical equilibrium with free surfactants. 

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