Non-ideal behavior of mixed micelles of cationic gemini surfactants with varying spacer length and anionic surfactants: A conductimetric study

• Type: Article in International Scientific Journal
• Date: 2008

Authors

Yujie J Wang (Author) Other; Eduardo F Marques (Author) FCUP

Journal

Title: Journal of Molecular Liquids

Vol. 142

Pages: 136-142

ISSN: 0167-7322

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 45 Citations

Scopus - 47 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-003-WZ2

DOI: 10.1016/j.molliq.2008.06.001

Abstract (EN): Mixtures of cationic and anionic surfactants (catanionic mixtures) are often highly non-ideal, exhibiting strong synergism in their interfacial properties, manifested for instance in significant reduction of the mixture critical micelle concentration (cmc) and enhanced adsorption onto surfaces. The magnitude of such effects is of fundamental interest and has important application-related uses (e.g. in detergent formulation). In this work, the micellization process of mixtures of cationic gemini surfactants of the alkanediyl-alpha,omega-bis (alkyl dimethylammonium bromide) type, denoted by 12-n-12 (where it is the spacer length), with several common anionic surfactants has been investigated by electric conductivity. For the purpose of comparison. cationic-cationic mixtures, where dodecyltrimethylammonium bromide is the second cationic surfactant, have also been investigated. The cationic/anionic mixtures show relatively significant deviations from ideal behavior, depending on the structure of the gemini surfactant and the anionic surfactant. The interaction parameter beta(12), within Rubingh's non-ideal model for mixed micelles, has been calculated for each mixture, as well as the mixed micelle composition as a function of mixture composition. The observed synergism in the different mixtures is interpreted in terms of the molecular structure of the surfactants and corresponding head-head and chain-chain interactions.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 7