Polymeric surfactants, advantage

The extremely low CMCs have been advantageous for several applications, since only traces of polymer are required to form micelles. High dilution effects, that are problematic in the case of classical surfactants, do not alter polymeric micelles. The surface activity at the air - water, of the amphiphilic block copolymer or polymeric surfactants must be different from the classical surfactants, because of their much lower diffusion coefficients and their much complex conformations. 

In addition, the polymeric surfactant, necessary as a stabilizer during the emulsion polymerization, becomes, after drying of the latex, a constituent of the final paint film. This opens therefore the possibility for controlling the mechanical and surface properties of the film. The main advantage of polymeric surfactants is their double role, as stabilizer of the latex and modifier, i.e. as a plasticizer of the final polymer product. 

PPO), and CO- and tri-block variations of these structures. Polymeric surfactants interact with the surface in very different ways than low molecular weight surfactants. In most cases, it is believed that the hydrophobic moiety of the surfactant binds to the surface, exposing the hydrophilic portion to the run buffer. Polymeric surfactants have the advantage in that they can form effective coatings at low concentrations however, they are typically not as stable as their low molecular weight counterparts. 

Other applications of alcohol alkoxylates also include textile lubricants, agricultural chemicals, rinse aid formulations, and personal care products. Polyoxyethylene block copolymers exhibit properties similar to surfactants, such as the presence of micelles in aqueous solutions, micelle structure, and association number, and are therefore termed polymeric surfactants. These diverse subsets of nonionic surfactants are unique and offer several advantages in manufacturing, and they could be designed for specific uses and applications. A complete Surfactant Science Series volume dedicated to the chemistry, physicochemical properties, applications, and toxicity was published in 1996. Because of these beneficial attributes, alcohol ethoxylates and alcohol alkoxylates are the most important nonionic surfactants in terms of volume usage in consumer products. 

The macromolecular surfactants possess considerable advantages for use in cosmetic ingredients. The most commonly used materials are the ABA block copolymers, with A being poly(ethylene oxide) and B polyfpropylene oxide) (Pluronics). On the whole, polymeric surfactants have much lower toxicity, sensitization and irritation potentials, provided they are not contaminated with traces of the parent monomers. As will be discussed in the section on emulsions, these molecules provide greater stability and in some cases they can be used to adjust the viscosity of the cosmetic formulation. 

Polymeric surfactants have significant advantages over monomeric surfactants because they can anchor onto the dispersed phase at several sites at the... 

Thin liquid films have proven their advantages in the study of interaction forces in foam, emulsion, and wetting films stabilized by various types of surfactants see, for example. Refs. l-3]. DLVO and non-DLVO surface forces that stabilize these films have been established in many cases the relation between surface forces and film stability has also been found. Recently, several authors have reported results of model experiments with thin liquid films (foam, emulsion and wetting films) stabilized by polymeric surfactants. In our laboratories all three types of films from aqueous solutions of A-B-A triblock copolymers [4—6] or AB hydrophobically modified inulin [8-10] have been studied. The corresponding disperse systems (foams, emulsions, suspensions) stabilized by AB polymeric surfactants have also been studied extensively see, for example. Refs. [11-14]. It was supposed that the stabilizing forces are steric surface forces but they have not been directly proven and quantitatively studied. 

CE has been used for the analysis of anionic surfactants [946,947] and can be considered as complementary to HPLC for the analysis of cationic surfactants with advantages of minimal solvent consumption, higher efficiency, easy cleaning and inexpensive replacement of columns and the ability of fast method development by changing the electrolyte composition. Also the separation of polystyrene sulfonates with polymeric additives by CE has been reported [948]. Moreover, CE has also been used for the analysis of polymeric water treatment additives, such as acrylic acid copolymer flocculants, phosphonates, low-MW acids and inorganic anions. The technique provides for analyst time-savings and has lower detection limits and improved quantification for determination of anionic polymers, compared to HPLC. 

The reaction described in this example is carried out in miniemulsion.Miniemulsions are dispersions of critically stabilized oil droplets with a size between 50 and 500 nm prepared by shearing a system containing oil, water,a surfactant and a hydrophobe. In contrast to the classical emulsion polymerization (see 5ect. 2.2.4.2), here the polymerization starts and proceeds directly within the preformed micellar "nanoreactors" (= monomer droplets).This means that the droplets have to become the primary locus of the nucleation of the polymer reaction. With the concept of "nanoreactors" one can take advantage of a potential thermodynamic control for the design of nanoparticles. Polymerizations in such miniemulsions, when carefully prepared, result in latex particles which have about the same size as the initial droplets.The polymerization of miniemulsions extends the possibilities of the widely applied emulsion polymerization and provides advantages with respect to copolymerization reactions of monomers with different polarity, incorporation of hydrophobic materials, or with respect to the stability of the formed latexes. 

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