Precipitation of Mixtures of Anionic and Cationic Surfactants: III. Effect of Added Nonionic Surfactant

✍ Scribed by Bor-Jier Shiau; Jeffrey H. Harwell; John F. Scamehorn

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 471 KB
• Volume: 167
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.1994.1368

✦ Synopsis

The precipitation of an anionic surfactant by a cationic surfactiant in the presence of a nonionic surfictant is examined. The precipitation domains for sodium dodecyl sulfate/dodecylpyridinium ehloride were measured over a wide range of surfactant concentrations as a function of nonylphenol polyethoxylate concentration. Increasing the nonylphenol polyethoxylate concentration decreases the tendency for precipitation to occur. A model for predicting precipitation domains in ternary surfactant mixtures has been developed and verified experimentally. The model allows the nonionic surfactant to affect the precipitation behavior only by lowering the critical micelle concentration of the mixture. Small deviations between theory and experiments along part of the anionic-rich micelle boundary result from adsorption of SDS on the precipitate which gives the microcrystals a negative charge and prevents their growth to a visible size. (1) 1994 Academic Pres. Inc.