A ternary mixture of surfactants for medial purposes. Analyzing the thermodynamic of micellization models

ERICA PATRICA SCHULZ; JOSÉ LUIS RODRÍGUEZ; ROSANNA M. MINARDI ; PABLO C. SCHULZ

Guimaraes/Braga

Congreso; 6th Iberian Meeting on Colloids and Interfaces - RICI6; 2015

Centre of Physics of University of Minho (CFUM), Braga

Surfactant mixtures are used in most surfactant applications instead of pure amphiphiles because the mixtures often have enhanced properties when compared to the sum of properties of the pure components (synergism). The aqueous tricomponent surfactant mixture dodecyltrimethylammonium bromide (DTAB), sodium 10-undecenoate (SUD), sodium dodecanoate (SDD) has been studied over the complete triangular diagram and a coacervate (coexistence of two immiscible liquid phases having the same components and different concentrations) domain has been delimited. The mixtures do not prepicipitate in any proportion, a desired feature for many useful applications. In general the system behaves non-ideally, presenting a positive deviation of the critical micelle concentration CMC in a wide region. The Multicomponent Regular Solution Theory (MRST) [1] significantly subestimates the experimental CMCs and thus the applicability of the MRST is discussed. The biocide properties of DTAB and SUD against microorganisms, the high CMCs that ensure high concentrations of biologically active monomers and the possibility of having a system that remains liquid in any proportion, make the present system attractive for the design of bactericide and antifungal preparations for medicine, food and cosmetic industries.