Micelle translucence

Unsaturated polyesters with neutralized terminal carboxyl acid groups (EUP) are efficient emulsifiers which, at a sufficient concentration, may form aqueous microemulsions. Micro emulsions are liquid dispersions of translucent (opalescent or transparent) appearance. Their disperse phase contains particles of diameters between 20 and 80 nm which closely approaches the diameters (5-15 nm) of micelles [114]. 

The target HLB can be obtained by using a mixture of anionic surfactant (HLB = 9.4) and nonionic surfactant HLB = 16.7) in the right proportions (1 3.75 based on the formula in Table 3). Such mixing of anionic and nonionic surfactants is expected to lower the individual CMC s and thus an increase of the soil solubilization capacity. The surfactants in the product should be in spherical micelle phase to give a transparent/translucent appearance and small viscosity (Table 6). 

Blends of Polypropylene and Poly(Methyl Methacrylate). In seeking explanations for the experimental observations in blend degradations, it is important to consider the form in which the polymer is being degraded. Since compatibility, especially in polymers as unlike chemically as PP and PMMA, is the exception rather than the rule and since the blend samples were translucent, it seems most likely that the low concentration component, PMMA, is dispersed as discrete micelles in a matrix of PP. Thus, any interaction between the degradation reactions of the two components must occur across a fairly well defined phase boundary. Because of the severe restrictions on the motion of macromolecules... 

Microemulsions are clear (transparent and translucent are also used in the literature), thermodynamically stable, isotropic liquid mixtures of oil, water, and surfactant, frequently in combination with a cosurfactant. The aqueous phase may contain salt(s) and/or other ingredients, and the oil may actually be a complex mixture of different hydrocarbons and olehns. In contrast to ordinary emulsions, microemulsions form upon simple mixing of the components and do not require high shear conditions generally used in the formation of ordinary emulsions. Microemulsions tend to appear clear due to the small size of the disperse phase. However, clear appearance (transparency) may not be a fundamental property. Sometimes microemulsion may not look clear to the naked eye in the case where dark viscous oil exists. The solution may not be purely transparent because it contains aggregates of micelles. Quite often, we still use these terms, even in this book. Probably we should simply use the term homogeneous solution. 

These are transparent or translucent systems covering the size range from 5 to 50nm. Unlike emulsions and nanoemulsions (which are only kinetically stable), microemulsions are thermodynamically stable as the free energy of their formation is either zero or negative. Microemulsions are better considered as swollen micelles normal micelles can be swollen by some oil in the core of the micelle to form O/W microemulsions. Reverse micelles can be swollen by water in the core to form W/O microemulsions. 

Microemulsions are a special class of dispersions (transparent or translucent) which actually have little in common with emulsions, and are better described as swollen micelles. The term microemulsion was first introduced by Hoar and Schulman [1,2] who discovered that the titration of a milky emulsion (stabilised by a soap, such as potassium oleate) with a medium-chain alcohol such as pentanol or hexanol led to the production of a transparent or translucent system. A schematic representation of the titration method adopted by Schulman and coworkers is given below ... 

A rough guide to the dimensions of micelles, micellar solutions and macroemulsions is as follows Micelles, R<5 run (they scatter Htde light and are transparent) macroemulsions, R>50 nm (opaque and milky) micellar solutions or microemulsions, 5-50nm (transparent, 5-lOnm, translucent 10-50run). 

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