Polymer-surfactant aggregates applications

One of the most important features of these analogues is their ability to be further cross-linked. The feasibility of the post-polymerization was demonstrated by the application of UV light induced polymerisation of the diynoic galactonamide 32b, which resulted in polymers retaining the superstructure of the surfactant aggregates.167 Similar observations were made for the dodecyl galactonamides 32a, which open up a route to the construction of pre-defined chiral nano-objects, which can be then stablized after assembly. 

The role of the surfactants is two-fold first, to provide a locus for the monomer to polymerise, and second, to stabilise the polymer particles as they are formed. In addition, surfactants aggregate to form micelles (above the cmc), and these can solubilise the monomers. In most cases a mixture of anionic and nonionic surfactant is used for the optimum preparation of polymer latexes. Cationic surfactants are seldom used, except for specific applications where a positive charge is required on the surface of the polymer particles. 

An interesting application of aqueous IL microemulsions is to develop IL polymer materials incorporating enzymes that can be used as active, stable, and reusable biocatalysts [65].The IL l-vinyl-3-ethylimidazolium bis(trifluoromethylsulfonyl) amide ([veim][Tf2N] see Scheme 13.2) was used as the continuous phase. Incorporation of proteins in IL-based polymer frameworks is generally difficult because they are insoluble in most ILs.To overcome this limitation, the authors first employed water/Tween-20/[veim][TfjN] microemulsions to solubilize the enzyme in an IL phase and then incorporated the enzyme within these surfactant aggregates into IL polymer frameworks via polymerization in the presence of an IL-soluble cross linker and initiator. 

The unique surface characteristics of polysiloxanes mean that they are extensively used as surfactants. Silicone surfactants have been thoroughly studied and described in numerous articles. For an extensive, in-depth discussion of this subject, a recent chapter by Hill,476 and his introductory chapter in the monograph he later edited,477 are excellent references. In the latter monograph, many aspects of silicone surfactants are described in 12 chapters. In the introduction, Hill discusses the chemistry of silicone surfactants, surface activity, aggregation behavior of silicone surfactants in various media, and their key applications in polyurethane foam manufacture, in textile and fiber industry, in personal care, and in paint and coating industries. All this information (with 200 cited references) provides a broad background for the discussion of more specific issues covered in other chapters. Thus, surfactants based on silicone polyether co-polymers are surveyed.478 Novel siloxane surfactant structures,479 surface activity and aggregation phenomena,480 silicone surfactants application in the formation of polyurethane foam,481 foam control and... 

Polymeric micelles form stable pseudostationary phases with a critical micelle concentration of virtually zero (aggregation number of 1), and are tolerant of high organic solvent concentrations in the electrolyte solution. Mass transfer kinetics are slow compared with conventional surfactant micelles, and peak distortion from mass overloading is a problem for some polymer compositions. Preliminary studies indicate that polymeric surfactants are effective pseudostationary phases in micellar electrokinetic chromatography, but only a limited number of practical applications have been demonstrated, and uptake has been slow. 

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