Ternary amphiphiles

FIG. 13 Phase diagram of a vector lattice model for a balanced ternary amphiphilic system in the temperature vs surfactant concentration plane. W -I- O denotes a region of coexistence between oil- and water-rich phases, D a disordered phase, Lj an ordered phase which consists of alternating oil, amphiphile, water, and again amphi-phile sheets, and L/r an incommensurate lamellar phase (not present in mean field calculations). The data points are based on simulations at various system sizes on an fee lattice. (From Matsen and Sullivan [182]. Copyright 1994 APS.)... 

Note that Fig. 13 still has little similarity with the experimental phase iiagram of ternary amphiphilic systems, Fig. 3b. In particular, the region of... 

G. Gompper, M. Kraus. Ginzburg-Landau theory of ternary amphiphilic systems. II. Monte Carlo simulations. Phys Rev E 47 4301- 312, 1993. 

T. Sakai, Y. Chen, and H. Ohashi, Real-coded lattice gas model for ternary amphiphilic fluids, Phys. Rev. E 65, 031503 (2002). 

Ternary Amphiphiles with Star-Like Shape... 

Liquid Crystal Honeycombs and Other Complex Phase Structures of T-Shaped Ternary Amphiphiles... 

Holmqvist, P. Alexandridis, P. Lindman, B. Phase behavior and structure of ternary amphiphilic block copolymer-alkanol-water systems comparison of poly(ethylene oxide) poly(propylene oxide) to poly(ethylene oxide) poly(tetrahydro-furan) copolymers. Langmuir 1997, 13 (9), 2471-2479. 

The biaxial nematic (NJ phase was first identified by Yu and Saupe in a ternary amphiphilic system composed of potassium laurate, 1-decanol and D2O. In such systems the constituent units are molecular aggregates, called micelles, whose size and shape are sensitive to the temperature and concentration the phase was found to occur over a range of temperature/concentration. There are obvious advantages in having a single-component, low-molar-mass thermotropic phase. The sugges-... 

Based on the concept of competitive polyphilicity, it was possible to increase the complexity of LC phases considerably [3, 4, 9, 137-140]. This concept was successfully applied to two types of T-shaped ternary amphiphiles, namely bolaamphiphiles [141, 142] and facile amphiphiles [143-147]. Both kinds of compounds are composed of rodlike aromatic cores, two end-groups, and one (T-shaped), two (X-shaped) or more chains attached laterally to the core. Numerous honeycomb-like... 

In the (EO)i7(BO),o/D20/p-xylene Alex-andridis et al. claimed the first, to their knowledge, reverse micellar cubic phase in a typical ternary amphiphile/water/oil system [143] before studying and reporting the system in more detail [144]. They report six mesophases and two solution phases at 25 °C. On increasing the polymer concentration along the polymer-water axis the phase sequence Lj (<22% polymer), I, (23-37%), Hi (42-54%), L (62-84%) is... 

The middle phase of ternary amphiphilic systems is quite intriguing because it is difficult to understand how the addition of a small amount of amphiphile to two immiscible fluids like oil and water can cause them to mix, producing a single isotropic phase. It is even more difficult to fashion a theory that can describe what the structure of this phase might be. 

Many of the phenomena in ternary amphiphilic systems also occur in mixtures of an AB diblock copolymer with A and B homopolymers (for a review, see Ref 9). We emphasize the similarity of these systems by showing that the same models can be used to describe their properties. 

The lattice model for ternary amphiphilic systems can now be constructed [33,36]. A binary variable 5, = 1 indicates whether a lattice site i is occupied by a polar or hydrophobic species, and a second variable /, = 1,0 indicates whether that species is part of a surfactant molecule or not. The Hamiltonian for these variables is... 

The origin of the Ginzburg-Landau approach lies in the study of the thermal behavior near critical points, which is characterized by a set of universal critical exponents. One of the advantages of this approach is that many techniques that have been developed in this context can be applied to Ginzburg-Landau models of ternary amphiphilic systems as well. 

Other models for ternary amphiphilic systems are based on mixtures of hard spheres and ellipsoids with Lennard-Jones interactions [58] or on mixtures of hard spheres and diatomic hard-sphere molecules [59]. Such models have been studied by molecular dynamics simulations. 

Much ofthe phase behavior of binary and ternary amphiphilic systems has been reproduced by the models that we have described. Distinguishing which behavior is characteristic of generic multicomponent systems and which is particular to amphiphilic systems has been one of the successes of the microscopic approach, which is able to describe both kinds of systems. 

To describe the dynamical properties of ternary amphiphilic liquids, not only the order parameter field d>(r, t) [and the amphiphile concentration pit, /)] but also the hydrodynamic flow of the fluid, which is described by a velocity field v(r, /), and the pressure field pir, t) have to be taken into account. The dynamics of these five fields is then determined by a set of Langevin equations. 

Predictions (61) and (62) have been qualitatively confirmed in experiments for a symmetrical diblock copolymer melt [147] (see Fig. 12). We show in Sec.V.B that these systems are indeed closely related to ternary amphiphilic systems, and, in the weak segregation regime, can be described by the same Ginzburg-Landau models. 

Figure 2 Schematic representation of Winsor-type equilibria in a ternary amphiphilic system. Between the water-oil side of the phase triangle and the base of the three-phase triangle there is a narrow two-phase zone at very low surfactant content that corresponds to the equilibrium between the excess phases that contain very little amounts of surfactant (about the critical micelle concentration). (From Ref 34.)...

Structure functions and interfacial mean curvatures in a ternary amphiphilic system Ci2Es/water/ rr-octane... 

Abstract Partial structure functions and mean curvatures of a ternary amphiphilic system consisting of water, n-octane and nonionic amphiphile C12E5 with equal volume fraction of oil and water have been studied by means of small-angle neutron scattering (SANS). Isotopic contrast variation technique was used to obtain suitable scattering contrasts of oil and water. We observed that the cross partial structure functions, that arise from the correlation between water-surfactant or oil-surfactant, change sign when the temperature... 

Amphiphiles, the representatives of which are soap, surfactant and lipid, have a hydrophilic polar head and lipophilic nonpolar tails. They always remain on the interface between water and oil and form monolayers of surfactants in a water/oil/amphiphile ternary system. This monolayers or interfacial film reduce the surface tension between water and oil domains. In a three-component system the surfactant film exists in various topologically different structures such as micelles, vesicles, bicontinuous microemulsions, hexagonal arrays of cylinders or lamellar structures depending upon the pressure, temperature and the concentration of the components [1,2]. Microemulsions are thermodynamically stable, isotropic and transparent mixtures of ternary amphiphilic systems. When almost equal volume fractions of water and oil are mixed with a dilute concentration of surfactants, they take... 

The space-averaged mean curvatures water-surfactant interfacial area A , the oil-surfactant interfacial area Ag, the interfacial area at the mid-plane of surfactant film and... 

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