Phase behavior and thermodynamics of a mixture of cationic gemini and anionic surfactant

• Type: Article in International Scientific Journal
• Date: 2006

Authors

Wang, YJ (Author) FCUP; Bai, GY (Author) FCUP; Marques, EF (Author) FCUP; Yan, HK (Author) Other

Journal

Title: Journal of Physical Chemistry B

Vol. 110

Pages: 5294-5300

ISSN: 1520-6106

Publisher: American Chemical Society

Indexing

ISI Web of Knowledge - 41 Citations

Scopus - 42 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-004-MPS

DOI: 10.1021/jp054323z

Abstract (EN): We present the phase behavior and thermodynamics of the catanionic mixture of the gemini surfactant hexanediyl-alpha,omega-bis(dodecyidimethylammonium bromide), designated here as 12-6-12Bn(2), and sodium dodecyl sulfate (SIDS) over the full range of composition, at the water-rich corner. Visual and turbidity measurements of the mixtures provide some basic macroscopic information on phase behavior. The structure of the aggregates formed spontaneously in the mixtures has been observed with TEM. As the molar fraction of SDS, X(SDS), is increased, at constant total surfactant concentration, the aggregation morphologies change gradually from gemini-rich micelles, through multiphase regions containing a precipitate (catanionic surfactant) and a vesicle region, to SDS-rich micelles. From isothermal titration calorimetry measurements, the phase boundaries and corresponding enthalpy changes for phase transitions have been obtained. The formation of the different microstructures, in particular, the spontaneously formed vesicles in the SDS-rich side, is discussed on the basis of geometric and electrostatic effects occurring in the SDS-gemini mixture.

Language: English

Type (Professor's evaluation): Scientific