Amphiphiles theoretical considerations

The theoretical and experimental investigations of rupture and permeability of amphiphile bilayers are valuable also for the understanding of some microstructural effects in interfacial layers and phases of small volumes. The interpenetration of macroscopically measured quantities, e.g. r and W, by means of molecular statistical models seems to be most interesting and useful. As first attempts in this respect, a molecular statistical lattice model of such bilayers has been proposed [427] and a lattice model of such bilayers has been studied by means of Monte Carlo simulation by Chowdhury and Stauffer [429]. The results obtained have been compared with some experimental data presented in this Section. Clearly, the combination of macro and micro considerations is a promising way to obtain a deeper insight into the properties of matter and, especially, of interfacial layers and phases of small volumes. 

The similarities between non-ionic micelles and globular proteins (Nemethy, 1967 Schott, 1968 Jencks, 1969) render micelles potentially useful as models for the investigation of hydrophobic interactions. Indeed, the stability of non-ionic micelles has been treated theoretically in terms of hydrophobic interactions (Poland and Scheraga, 1965). Since the critical micelle concentration is related to the degree and nature of the hydrophobic interactions of the amphiphile, its valne in the presence of additives and at different temperatures can be nsed as a quantitative measure of the effect of these variables on the hydrophobic interactions. In spite of the similarities between proteins and micelles, considerable caution is warranted in extrapolating the results obtained from micellar models to the more complex protein systems. 

Lyotropic liquid crystals acquire their anisotropic properties from the mixing of two or more components. One component is amphiphilic and contains a polar head group, the second component is usually water. Lyotropic liquid crystals occur abundantly in nature, particularly in all living systems. The most familiar example of a lyotropic liquid crystal is soap in water. During the last few years considerable progress has been made toward understanding the experimental and theoretical aspects of the method reviewed in this book. 

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