Surfactant-polymer assemblies

Expanding the synthesis tool box beyond surfactant self-assembly 2.6.1 Block co-polymers templates... 

Biological systems provide numerous examples of self-assembled objects. Owing to the relatively weak interactions involved, a self-assembled structure is much more sensitive and responsive to its environment than a more rigid structure held together by covalent bonds. Unlike processes involving simple surfactants, polymers, and nanoparticles, self-assembly processes in biological systems are usually directional and functional and often lead to the formation of extremely complex structures. For example, the three-dimensional structure adopted by a protein in solution is critical to the protein s function, and this structure is determined by both strong (covalent) and weak... 

Surfactant-polymer interactions in an aqueous solution have been studied by many researchers [132], and the adsorption and surface-induced self-assembly of the surfactant at the solid-aqueous interface have been recently studied [133]. On the other hand, these subjects have been rarely studied for oil solutions. The surfactant-polymer interaction in oil and the surface-induced self-assembly of surfactants at the oil-solid interface are important for further research studies to enhance the polymerization at the interface of the liquid/solid in reversed micellar solutions. 

Compared to surfactant self-assembling systems, the parameter space for polymer co-assembly is notably larger, and guidance of some sort (e.g. to assist interpretation of experiments, as discussed above) is timely. From previous work, we know... 

This present chapter describes micelle formation in isotropic solutions, while surfactant self-assembly into other structures is treated in other chapters in this volume, as well as surfactant self-assembly in the presence of polymer chains and solid surfaces. 

POLYMERS MAY CHANGE THE PHASE BEHAVIOUR OF INFINITE SURFACTANT SELF-ASSEMBLIES... 

KEISHIRO SHIRAHAMA is Professor of physical chemistry of St a University, Saga, Japan. He received a doctor of science from Kyushu University. His academic interest is directed to amphiphilic molecular assemblies such as surfactant-polymer complex, mixed micelle, and vesicle as well as random phenomena in physicochemical systems. 

The primary aim is to introduce the current concepts used to interpret the properties of homogeneous, optically transparent, self-assembling aqueous solutions of small molecule surfactants that form into association colloids composed of charged or uncharged surfactants into micelles, miaoemul-sions, vesicles, or other mesophases. Pseudophase models are used to interpret chemical reactivity in surfactant solutions. Large surface-active molecules such as proteins, starches, and polymers are not considered. Much of the information is on surfactant solutions at room temperature and atmospheric pressure because most of the important properties, concepts, and unanswered questions can be developed at ambient conditions. Effects of additives such as salts, alcohols, and oils, and temperature are introduced briefly. Many introductory books include substantial sections on surfactant self-assembly. " Current research on a variety of topics is periodically reviewed in Current Opinion in Colloid and Interface Science. 

AFM observations on HOPG in fluid-tapping mode were carried out for a nanoscale understanding of surface-induced self-assembly of the dendritic surfactant polymer. 

Polymer micelles in aqueous medium are typically obtained with hydrophobic-hydrophiKc, so-called amphiphilic, block and graft copolymers. Analogous to conventional low-molecular surfactants, and in a selective solvent of one of the blocks, such polymeric surfactants self-assemble into nanoparticles with well-defined sizes and structures. 

Bronich, T.K., Ouyang, M., Eisenberg, A., Kabanov, V.A., Szoka, F.C. and Kabanov, A.V. (2000) Reactive stabUization of vesicles from cationic surfactant self-assembled on anionic block ionomer template. ACS Po/ym. Prepr. (Div. Polym. Chem.), 41(1), 1645-1646. 

Singh PK, Kumbhakar M, Pal H, Nath S (2008) Effect of electrostatic inteiactimi on the location of molecular probe in polymer-surfactant supramolecmar assembly a solvem relaxation study. J Phys Chem B 112 7771-7777... 

The mesogen structures may be formed not only by covalent bonds, but also by non-covalent interactions, such as hydrogen bonds, ionic interactions, and metal coordination [71]. A recent example [72] of this concept comprised the self-assembly of complex salts into stable hierarchical aggregates with a dense core and a diffuse shell. These materials were made from diblock copolymers poly(acrylic acid)-block-poly(acrylamide) and the cationic surfactant dodecyltrimethylammonium. Due to non-covalent interactions the surfactant/polymer aggregates exhibited a liquid crystalline structure of cubic symmetry. 

Manne S 1997 Visualizing self-assembly Force microscopy of ionic surfactant aggregates at solid-liquid interfaces Prog. Colloid Polym. Sol. 103 226-33... 

Functionalized polyelectrolytes are promising candidates for photoinduced ET reaction systems. In recent years, much attention has been focused on modifying the photophysical and photochemical processes by use of polyelectrolyte systems, because dramatic effects are often brought about by the interfacial electrostatic potential and/or the existence of microphase structures in such systems [10, 11], A characteristic feature of polymers as reaction media, in general, lies in the potential that they make a wider variety of molecular designs possible than the conventional organized molecular assemblies such as surfactant micelles and vesicles. From a practical point of view, polymer systems have a potential advantage in that polymers per se can form film and may be assembled into a variety of devices and systems with ease. 

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