Ethoxylated nonionic surfactants microemulsions based

Ethoxylated fatty esters, emulsifiers, detergents, and dispersants, 8 710t Ethoxylated nonionic surfactants, microemulsions based on, 16 428 Ethoxylated surfactants, 24 142, 148 Ethoxylates, 24 149-151 Ethoxylation, fatty amines, 2 523 2-Ethoxypyridine, 21 104 Ethoxyquin, 10 854 13 42t, 51 2-Ethyl-1-butanol... 

NMR self-diffusion measurements indicated that all microemulsions consisted of closed water droplets and that the structure did not change much during the course of reaction. Hydrolysis was fast in microemulsions based on branched-chain anionic and nonionic surfactants but very slow when a branched cationic or a linear nonionic surfactant was employed (Fig. 11). The cationic surfactant was found to form aggregates with the enzyme. No such interactions were detected with the other surfactants. The straight-chain, but not the branched-chain, alcohol ethoxylate was a substrate for the enzyme. A slow rate of triglyceride hydrolysis for a Ci2E4-based microemulsion compared with formulations based on the anionic surfactant AOT [61,63] and the cationic surfactant cetyltrimethylammonium bromide (CTAB) [63] was observed in other cases also. Evidently, this type of lipase-catalyzed reaction should preferably be performed in a microemulsion based on an anionic or branched nonionic surfactant. Nonlipolytic enzymes such as cholesterol oxidase seem to function well in microemulsions based on straight-chain nonionic surfactants, however [64]. CTAB was reported to cause slow inactivation of different types of enzymes [62,64,65] and also, in the case of Chromobacterium viscosum lipase [66], to provide excellent stability. 

Three microemulsions liquid crystalline gel formulations from Croda, Inc. based on lower EO nonionic surfactants and ethoxylated phosphates for clear hair gel products are shown inTable 6 [15]. One contains cyclomethicone for reduced oily feeling, and another contains a high level of polyol for humectant effect, classifying it as a curl activator. 

Microemulsion gels are usually based on nonionic ethoxylated ether surfactants based on oleyl, lauryl, or isocetyl alcohol either alone or in combination with ethoxylated phosphate esters. Long hexagonal liquid crystalline structures present in the gel can vibrate when the container is tapped, resulting in a ringing gel [18], Table 10 presents a versatile ringing gel microemulsion base formula from ICI [16] for three clear cosmetic products. 

The pore morphology of microemulsion-based solid polymer depends on the initial microstructure of the microemulsion as determined by the type of surfactant and cosurfactant in addition to composition. Some examples of nonionic surfactants used for microemulsions are Emsorb 6916 (sorbitan monolaurate), Neodol 91-5 (primary alcohol ethoxylate), and Trycol (polyoxyethylene alkylphenol), while sodium dodecyl sulfonate is commonly used as the anionic surfactant. Figure 3.15... 

Examples of different emulsification routes based on the PIT method and the corresponding droplet sizes obtained are shown in Fig. 12. In this example [7,115], the emulsification of a polar oil, cetyl isononanoate, was performed with a surfactant mixture consisting of a long-chain ethoxylated alcohol (Cis/igEz) and glyceryl monostearate (GMS) nonionic surfactants. It was shown that in order to obtain nanometer-size droplets in the system studied, either a liquid crystalline phase or a bicontinuous microemulsion should be formed during emulsification [7]. 

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