Micelles vesicles

J. C. Lang, Physics of Amphiphiles Micelles, Vesicles and Microemulsions, Soc. Italiana di Fisica, XC Corso, Bologna, 1985. 

V. Degiorgio and M. Corti, Phjsics ofyimphiphiks Micelles, Vesicles, and Microemulsions, Elsevier Science Publishing Co., New York, 1985. 

V. Degiorgio, M. Corti, eds. Physics of Amphiphiles Micelles, Vesicles and Microemulsions. Amsterdam North-Holland, 1985 W. M. Gelbart, A. Ben-Shaul, D. Roux, eds. Micelles, membranes, microemulsions and monolayers. Berlin Springer, 1994. 

S. Carra, M. Morbidelli, and G. Storti, in Proceedings of the International School of Physics Enrico Fermi, Course XC Physics of Amphiphiles Micelles, Vesicles and Microemulsions (V. Degiorgio and M. Corti, ed.), North-Holland, Amsterdam, 1985, pp. 483-512. 

The area of colloids, surfactants, and fluid interfaces is large in scope. It encompasses all fluid-fluid and fluid-solid systems in which interfacial properties play a dominant role in determining the behavior of the overall system. Such systems are often characterized by large surface-to-volume ratios (e.g., thin films, sols, and foams) and by the formation of macroscopic assembhes of molecules (e.g., colloids, micelles, vesicles, and Langmuir-Blodgett films). The peculiar properties of the interfaces in such media give rise to these otherwise unlikely (and often inherently unstable) structures. 

As mentioned earlier, a great deal of literature has dealt with the properties of heterogeneous liquid systems such as microemulsions, micelles, vesicles, and lipid bilayers in photosynthetic processes [114,115,119]. At externally polarizable ITIES, the control on the Galvani potential difference offers an extra variable, which allows tuning reaction paths and rates. For instance, the rather high interfacial reactivity of photoexcited porphyrin species has proved to be able to promote processes such as the one shown in Fig. 3(b). The inhibition of back ET upon addition of hexacyanoferrate in the photoreaction of Fig. 17 is an example of a photosynthetic reaction at polarizable ITIES [87,166]. At Galvani potential differences close to 0 V, a direct redox reaction involving an equimolar ratio of the hexacyanoferrate couple and TCNQ features an uphill ET of approximately 0.10 eV (see Fig. 4). However, the excited state of the porphyrin heterodimer can readily inject an electron into TCNQ and subsequently receive an electron from ferrocyanide. For illumination at 543 nm (2.3 eV), the overall photoprocess corresponds to a 4% conversion efficiency. 

Figure 10.11 Adaptive response nature of c/s-double bonds in N-cardanyltauramide that undergoes micelle-vesicle-micelle transition with respect to temperature.

Although the notion of monomolecular surface layers is of fundamental importance to all phases of surface science, surfactant monolayers at the aqueous surface are so unique as virtually to constitute a special state of matter. For the many types of amphipathic molecules that meet the simple requirements for monolayer formation it is possible, using quite simple but elegant techniques over a century old, to obtain quantitative information on intermolecular forces and, furthermore, to manipulate them at will. The special driving force for self-assembly of surfactant molecules as monolayers, micelles, vesicles, or cell membranes (Fendler, 1982) when brought into contact with water is the hydrophobic effect. 

An additional point is that relatively high concentrations of surfactant, oil and cosurfactant are often used in microemulsions. Thus the volume of the microemulsion pseudophase is large and droplet-bound reactants are therefore diluted. Generally speaking, rate enhancements increase in the sequence microemulsions < micelles < vesicles simply because of a decrease in the volume of the micellar or droplet pseudophase. 

Ester hydrolysis Lecithin vesicles and CTABr micelles. Vesicles inhibited reaction Fatah and Loew, 1983... 

NC6H40)2P0.0Et + hydroxamates Dephosphorylations by mixed micelles, vesicles and hydrophobic hydroxamic acid compared Okahata et al., 1981... 

Intramolecular excimers have been used for probing bulk polymers, micelles, vesicles and biological membranes (Bokobza and Monnerie, 1986 Bokobza, 1990 Georgescauld et al., 1980 Vauhkonen et al., 1990, Viriot et al., 1983 Zachariasse et al., 1983). In particular, this method provides useful information on the local dynamics of polymer chains in the bulk (see Box 8.2). 

Protein is an excellent natural nanomaterial for molecular machines. Protein-based molecular machines, often driven by an energy source such as ATP, are abundant in biology. Surfactant peptide molecules undergo self-assembly in solution to form a variety of supermolecular structures at the nanoscale such as micelles, vesicles, unilamellar membranes, and tubules (Maslov and Sneppen, 2002). These assemblies can be engineered to perform a broad spectrum of functions, including delivery systems for therapeutics and templates for nanoscale wires in the case of tubules, and to create and manipulate different structures from the same peptide for many different nanomaterials and nanoengineering applications. 

This chapter discusses stereospecific intermolecular interactions in monolayers at the air-water interface, where surface-active molecules (surfactants) are partially oriented with respect to each other by the cooperative combination of interionic, hydrophobic, and hydrogenbonding forces. We believe that these reports should be of particular interest in relation to stereospecificity in assemblies such as micelles, vesicles, and bilayer membranes, where their significance has been largely ignored. 

Ollivon M, Eidelman O, Blumenthal R, Walter A. Micelle-vesicle transition of egg phosphatidylcholine and octyl glucoside. Biochemistry 1988 27 1695. 

The tendency of apolar side chains of amino acids (or lipids) to reside in the interior nonaqueous environment of a protein (or membrane/micelle/vesicle). This process is accompanied by the release of water molecules from these apolar side-chain moieties. The effect is thermodynamically driven by the increased disorder (ie., AS > 0) of the system, thereby overcoming the unfavorable enthalpy change (ie., AH < 0) for water release from the apolar groups. 

Introduction to the variety of types of surfactants, effect of surfactants on aqueous solution properties. Law of mass action applied to the self-assembly of surfactant molecules in water. Spontaneous self-assembly of surfactants in aqueous media. Formation of micelles, vesicles and lamellar structures. Critical packing parameter. Detergency. Laboratory project on determining the charge of a micelle. 

Figure 5.10 Self-organization of di-block copolymers. Block copolymers can form spherical and cylindrical micelles, vesicles, spheres with face-centered cubic (fee) and body-centered cubic (bcc) packing, hexagonally packed cylinders (hex) minimal surfaces (gyroid, F surface, and P surface), simple lamellae and modulated and perforated lamellae. (Adapted from Bucknall and Anderson, 2003.)...

We have already seen in Chapter 5, on self-organization, how and why amphiphilic molecules tend to form aggregates such as micelles, vesicles, and other organized structures. 

Matrix effect in oleat-micelles-vesicles transformations. Orig. Life Evol. 

Macrocyclic host molecules, medium-sized aggregates (microemulsions, micelles,vesicles, etc.) and mesoporous materials as catalysts... 

Lipid micellization Vesicles for encapsulation, controlled release, functional incorporation of proteins and mimicking of biological membranes Singh et al., 1995 Taylor et al., 2005 Sagalowicz et al., 2006 Mozafari et al., 2006... 

---