ABSTRACT
Apart from the bilayer lamellar Lα phase, all other uid lyotropic mesophases are based upon ordered arrangements of curved interfaces, separating the amphiphiles from the water regions. These ordered curved phases may be divided into three main structural classes: 2D packings of cylindrical interfaces (discontinuous phases), 3D packings of saddle surfaces (bicontinuous phases), and 3D packings of spherical/ellipsoidal interfaces (discontinuous phases). Furthermore, each of these three classes occurs in two variants, either oil-in-water (type I), where the interfaces have net mean curvature toward the lipid hydrocarbon chain regions, or water-in-oil (inverse, type II), where the interfaces curve toward the water regions and away from the hydrocarbon chains (Figure 2.2). Type I curved mesophases generally break up into disordered micellar solutions upon high dilution in water. Type II mesophases, on the other hand, are usually stable in the presence of an excess
2.1 Introduction ............................................................................................................................ 31 2.2 Amphiphile Self-Assembly and Lipid Packing Parameter ..................................................... 32 2.3 Interfacial Curvature .............................................................................................................. 33 2.4 Generic Lyotropic Phase Diagram..........................................................................................34 2.5 Factors Controlling the Preferred Interfacial Curvature ........................................................ 35 2.6 Curvature Elastic Energy........................................................................................................36 2.7 2D Hexagonal Phases, Type I and Type II ............................................................................. 38 2.8 Chain Packing Frustration ...................................................................................................... 38 2.9 3D Bicontinuous Cubic Phases, Type I and Type II ............................................................... 39 2.10 Sponge Phase .......................................................................................................................... 39 2.11 3D Ordered Micellar Phases, Type I and Type II ...................................................................40 2.12 Intermediate Phases ................................................................................................................ 42 2.13 Control of Phase Behavior ...................................................................................................... 42 2.14 Phase Transitions between Nonlamellar Phases ..................................................................... 43 2.15 Dispersed Nanoparticles of Nonlamellar Lipid Aggregates ...................................................44 2.16 Examples of Applications of Nonlamellar Phases..................................................................44 Acknowledgments ............................................................................................................................46 References ........................................................................................................................................46
