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Selection of surfactant pairs for optimization of interfacial properties
Author(s) -
Rosen Milton J.
Publication year - 1989
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/bf02660759
Subject(s) - pulmonary surfactant , critical micelle concentration , surface tension , micelle , monolayer , aqueous solution , chemistry , chemical engineering , thermodynamics of micellization , materials science , thermodynamics , organic chemistry , nanotechnology , physics , biochemistry , engineering
Guidelines are provided for the selection of surfactant pairs when synergism in various interfacial properties in aqueous media is desired. To maximize the reduction of the critical micelle concentration, the two surfactants should show strong attractive interaction in the mixed micelle; in order to maximize efficiency in surface tension reduction, strong interaction in the mixed monolayer at the aqueous solution/air interface (large negative β values is needed). The more surface‐active material should predominate in the mixture. When interaction is not strong, the two surface‐active materials used should have approximately equal surface activities and should be used at equimolar concentration in the aqueous phase. To minimize the surface tension ( γ ) of the solution, the surfactant‐surfactant attractive interaction in the mixed monolayer at the aqueous solution/air interface must exceed that in the mixed micelle. Optimization can be achieved by using two surfactants with approximately equal γ values at their respective critical micelle concentrations (CMC’s). When these γ values are not equal, the surfactant with the higher γ value at its CMC should have the smaller area/molecule at the surface. The greater the difference between attractive interaction at the interface and in the micelle, the lower the value of the surface tension.