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Effect of additives on the adsorption of sodium bis(2‐ethyl hexyl sulfosuccinate) at the air‐water interface studied by equilibrium and dynamic surface tension measurements
Author(s) -
Pedrosa Ana Belén,
Briz José I.,
Velázquez M. Mercedes
Publication year - 2002
Publication title -
journal of surfactants and detergents
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.349
H-Index - 48
eISSN - 1558-9293
pISSN - 1097-3958
DOI - 10.1007/s11743-002-0239-4
Subject(s) - chemistry , pulmonary surfactant , surface tension , adsorption , sodium , diffusion , chloride , inorganic chemistry , chromatography , analytical chemistry (journal) , thermodynamics , organic chemistry , biochemistry , physics
Using equilibrium and dynamic surface tension measurements, we have studied the effect of the addition of poly(sodium 4‐styrenesulfonate) (PSS), sodium chloride, and 1,4,7,10,13,16‐hexaoxyacyclooctadecane (18‐crown‐6) on the surface properties of sodium bis(2‐ethyl hexyl sulfosuccinate) (AOT). The addition of PSS or NaCl weakly increases the maximum packing of AOT, whereas the presence of 18‐crown‐6 slightly decreases the maximum surface coverage. The surfactant adsorption kinetics on the interface is a diffusion‐controlled process. The two asymptotic solutions at long times and at short times to the classic Ward Tordai equation were used to fit dynamic results. At long times there is evidence of the existence of an electrostatic barrier at high surfactant concentration when using pure AOT and AOT mixed with PSS. In binary mixtures of AOT with sodium chloride or 18‐crown‐6, the electrostatic barrier is not observed over the surfactant concentration range studied.