Amphiphilic block copolymer mixture

The research on microemulsions currently concentrates on even more complex mixtures. By adding amphiphilic macromolecules the properties of microemulsions can be influenced quite significantly (see Chapter 4). If only small amounts of amphiphilic block copolymers are added to a bicontinuous microemulsion a dramatic enhancement of the solubilisation efficiency is found [27,28]. On the other hand, the addition of hydrophobically modified (HM) polymers to droplet microemulsions leads to a bridging of swollen micelles and an increase of the low shear viscosity by several orders of magnitude [29]. 

Endo, H., Mihailescu, M., Monkenbusch, M., AUgaier, J., Gompper, G., Richter, D., Jakobs, B., Strey, R. and Grillo, I. (2001) Effect of amphiphilic block copolymers on the structure and phase behavior of oil-water-surfactant mixtures. /. Chem. Phys., 115, 580-600. 

Some phase diagrams of low-polydispersity amphiphilic block copolymers, exhibit areas of coexistence over a relatively wide range of composition (see Fig. 4) [32]. This is probably due to kinetic inertia or to the fact that at the borderline between two thermodynamically stable phases the energetic differences between two structures are marginal. Swelling these coexisting phases with a siliceous precursor affords a microphase-separated siliceous phase, which has the same structure as the binary mixture consisting of water and amphiphilic... 

P-12 - Mesostructure design using mixture of nonionic amphiphilic block copolymers... 

Amphiphilic block copolymers self-organize in aqueous mixtures to form polymeric micelles having a core of the hydrophobic block and a shell of the hydrophilic block. The cores can absorb additional hydrophobic low molecular weight compounds. The shells can be cross-linked to form capsules that are much more physically robust than the original micelles, as shown in Figure 11.10 (15). The uncross-linked inner phase can be dissolved by a good solvent to produce hollow capsules or serve as a site for trapping metal nanoparticles as catalysts. 

The impact of different surfactants (SDS, DOSS, CTAB and hexadimethrine bromide, bile salts °), nonionic and mixed micelles, and additives (neutral and anionic CDs," " tetraalkylammonium salts, organic solvents in EKC separations has been demonstrated with phenol test mixtures. In addition, phenols have been chosen to introduce the applicability of more exotic EKC secondary phases such as SDS modified by bovine serum albumin, water-soluble calixarene, " starburstdendrimers, " " cationic replaceable polymeric phases, ionenes, amphiphilic block copolymers,polyelectrolye complexes,and liposome-coated capillaries. The separation of phenols of environmental interest as well as the sources and transformations of chlorophenols in the natural environment have been revised. Examples of the investigation of phenols by EKC methodologies in aquatic systems, soil," " and gas phase are compiled in Table 31.3. Figure 31.3 illustrates the electromigration separation of phenols by both CZE and EKC modes. 

Alexandridis, P., Olsson, U. and Lindman, B., Phase behaviour of amphiphilic block copolymers in water-oil mixtures the Pluronic 25R4-water-p-xylene system, J. Phys. Chem., 100, 280-288 (1996). 

Abstract Amphiphilic block copolymers (BCPs) are used in a steadily growing number of applications and formulations such as cosmetics, detergents, coatings, and enhanced oil recovery. In most of these applications, BCPs are used in complex mixtures with normal surfactants to control the solution properties of the mentioned systems. In addition, these systems are used as templates for nanoparticle and mesoporous silica synthesis. Hence, a deeper understanding of the self-assembly processes and the formed structures is desirable to achieve a better control of the properties of the obtained inorganic materials. This article reviews the recent literature describing physicochemical aspects of the BCP/surfactant mixtures and attempts to identify some general features of the behavior of these systems. 

Amphiphilic block copolymers (BCPs) have been subject of numerous studies during the last few decades. This is due to the unique properties that arise from the incompatibility of the blocks, leading to a large number of different self-assembled structures and mesophases in the bulk or in selective solvents [1 ]. Studies on the interaction of BCPs with different types of surfactant are also of great relevance because these mixtures can be found in an important number of technical products ranging from paints to cosmetic products to pharmaceutical formulations. 

In Chapter 1, Murgia, Palazzo, and coworkers investigated the physicochemical behaviors of a binary IL bmimBF and water, and the ternary NaAOT, water and bmimBF mixtures essentially through the evaluation of the self-diffusion coefficients of the various chemical species in solution by PGSTE-NMR experiments. The diffusion of water molecules and bmimBF ions were found to be within different domains, which suggested that the systems were nanostructured with formation of micelles having positive curvature and a bicontinuous micellar solution for the former and the later systems, respectively. The remarkable differences between the two systems are attributed to the specific counterion effect between the aforementioned ILs and the anionic surfactant. In Chapter 2, Bermudez and coworkers focused on the characterization of small (conventional surfactants) and polymeric amphiphiles (block copolymers) in different types of ILs (imidazolium, ammonium. 

R Alexandridis, U. Olsson, P, Linse, B. Lindman, Structural polymorphism of amphiphilic block copolymers in mixtures with water and oil Comparison with solvent-free block copolymers and surfactant systems. In Amphiphilic Block Copolymers. Self-Assembly and Applications, Ed. P. Alexandridis, U. Olsson, B. Lindman, p. 169, Elsevier, Amsterdam (2000) (overview over the phase behavior of PEO-PPO block copolymers). 

Zhang, L., Lin, J. and Lin, S. (2007) Self-assembly behavior of amphiphilic block copolymer/nanoparticle mixture in dilute solution studied by self-consistent-field theory/density functional theory. Macromolecules, 40, 5582-91. 

In comparison with the materials synthesized in the presence of surfactants, the surface area of the hierarchically porous zirconium oxides obtained via the self-formation phenomenon is relatively lower. Furthermore, the synthesis temperature can affect the crystallinity of the final product [124,139]. Upon increase of the hydrothermal treatment temperature to 130 °C (generally reported to be 60-80 °C), thermally stable meso-macroporous zirconias with a nanocrystalline framework were prepared by using a mixture of amphiphilic block copolymer P123 and poly(ethylene oxide) surfactant Brij 56. 

Hydrogenation of a triple bond of dehydrolinalool was carried out at ambient pressure in a glass batch isothermal reactor installed in a shaker and connected to a gasometric burette. In the case of micellar catalysts based on amphiphilic block copolymers, different solvents providing the better swelling of micelle corona and access of the substrates to catalytic sites were used. For PS-b-P4VP based catalyst, toluene was used, while for PEO-b-P2VP based catalyst, a mixture of 30 vol. % water and 70 vol. % of isopropyl alcohol (/-PiOH) was emploied. 

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