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Determination of critical micelle concentration of surfactant by ultraviolet absorption spectra
Author(s) -
Suzuki Hiroshi
Publication year - 1970
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/bf02609491
Subject(s) - pulmonary surfactant , critical micelle concentration , chemistry , micelle , aqueous solution , sodium dodecyl sulfate , absorption (acoustics) , thermodynamics of micellization , analytical chemistry (journal) , inorganic chemistry , chromatography , organic chemistry , materials science , biochemistry , composite material
A method was investigated for determining the critical micelle concentration (CMC) by the shift of absorption maxima when an organic compound (I) with ultraviolet absorption was added to an aqueous solution of a surfactant. When I was added to the surfactant solution at higher concentrations (above the CMC), λ max of I approached the value in n ‐octane, since I was solubilized in the hydrocarbon atmosphere of the inner part of the surfactant micelle. At lower concentrations (below the CMC), however, I was present in the water phase and λ max approached the value in water. The curve of λ max vs. surfactant concentration declined from the high concentration values as the CMC was approached and at the CMC, the curve broke upward sharply. Then, it rose for some time and approached the value in water. N,N′‐diethylaniline was used because it exhibited larger shifts of λ max . The standard amount used was 0.002 ml/3–10 ml of aqueous solution of the surfactant. The CMC values obtained agreed with those obtained by the electric conductivity method, dye adsorption method and light scattering method, for surfactants such as tetradecyldimethylbenzylammonium chloride, sodium dodecyl sulfate and polyoxyethylene cetyl ether.