Amphiphilic mesophases

Generic Relationships between Non-Amphiphilic and Amphiphilic Mesophases of the "Fused Type... 

The cubic amphiphilic mesophases (Sic, Vi, and V2) from their interposition in the succession of mesophases Sic, Mi, Vi, G, V2, and M2, have generally been termed liquid crystalline like the optically anisotropic amphiphilic mesophases Mi, G, and M2. The cubic mesophases formed by non-amphiphilic globular molecules have however usually been termed plastic crystals. This nomenclature has obscured the fact that these plastic crystals are fundamentally liquid crystals rather than solid cyrstals and bear a relationship to the optically anisotropic non-amphiphilic smectic and nematic liquid crystals similar to that born by the amphiphilic cubic mesophases to the optically anisotropic neat (G) and middle (Mi and M2) liquid crystalline phases. 

Nature of the succession of amphiphilic mesophases of the fused type in relation to... 

Amphiphilic Cubic Mesophases Viscous Isotropic Phases. In Figure 1, at positions where a high concentration of globular micellar forms might be expected, the cubic viscous isotropic mesophases Sic, Vi, and V2 are encountered. This is further illustrated by Figure 5. These mesophases, because of their inclusion within the general sequence of amphiphilic mesophases ... 

Figure 5. Formation of the hexagonal, lamellar, and cubic amphiphilic mesophases by the interactions between fibrous, lamellar, and globular micelles,...

From this point of view, the following conditions must be satisfied for an amphiphilic mesophase to form ... 

Ref. 13 contains a more complete discussion of static quadrupolar effects for amphiphilic mesophases. That work also includes a treatment of counterion quadrupole relaxation for liquid crystalline systems a brief outline of this discussion is given in the next section. 

Gray, G.W. and Winsor, P.A. (1976) Generic relationships between non-amphiphilic and amphiphilic mesophases of fused type. Relationship of cubic mesophases (plastic crystals) formed by non-amphiphilic globular molecules to cubic phases of amphiphilic series. Adv. Chem. Ser., 152, 1-12. 

W. Helfrich, Amphiphilic mesophases made of defects. In eds. R. Bahan, M. Kleman and J.P. Poirier, Physics of Defects, North-Holland Publ. Co., Amsterdam, 1981. pp. 716-755. 

Quadrupole Splittings of Halide Ions in Amphiphilic Mesophases... 

The distribution of defects in mesophases is often regular, owing to their fluidity, and this introduces pattern repeats. For instance, square polygonal fields are frequent in smectics and cholesteric liquids. Such repeats occur on different scales - at the level of structural units or even at the molecular level. Several types of amphiphilic mesophase can be considered as made of defects . In many examples the defect enters the architecture of a unit cell in a three-dimensional array and the mesophase forms a crystal of defects [119]. Such a situation is found in certain cubic phases in water-lipid systems [120] and in blue phases [121] (see Chap. XII of Vol. 2 of this Handbook). Several blue phases have been modeled as being cubic centred lattices of disclinations in a cholesteric matrix . Mobius disclinations are assumed to join in groups of 4x4 or 8x8, but in nematics or in large-pitch cholesterics such junctions between thin threads are unstable and correspond to brief steps in recombinations. An isotropic droplet or a Ginsburg decrease to zero of the order parameter probably stabilizes these junctions in blue phases. 

The formation of conventional amphiphile mesophases is preceded by the aggregation of molecules in solution. Groups of two or three amphiphile molecules associate with reluctance. There is still an unfavorably large fraction of the hydrophobic parts of the molecules exposed to water. This situation continues until the formation of aggregates approaching the size of a micelle (Fig. 3). 

Quadrupole splittings of a covalent halogen compound in liquid crystals were first observed in Cl NMR spectra of CH2CI2 in polybenzyl-L-glutamate by Gill, Klein, and Kotowycs (14). Quadrupole splittings of halide ions in amphiphilic mesophases were first observed in 1971 by Lindblom, Winnerstrom, and Lindman (15). 

Figure 8.4. A schematic representation of the possible role of amphiphile mesophases in the stabilization of foams.

AMPHIPHILE MESOPHASES AND EMULSION STABILITY 303 Surfactant liquid crystal... 

Figure 9.12. Some potential roles of amphiphilic mesophases at or near emulsion interfaces.

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