Surfactant Counterion Research Articles

ChemInform Abstract: STUDIES OF AQUEOUS SODIUM DODECYL SULFATE SOLUTIONS BY ACTIVITY MEASUREMENTS

Chemischer InformationsdienstVolume 6, Issue 32 Article ChemInform Abstract: STUDIES OF AQUEOUS SODIUM DODECYL SULFATE SOLUTIONS BY ACTIVITY MEASUREMENTS TSUNETAKA SASAKI, TSUNETAKA SASAKISearch for more papers by this authorMICHIHIRO HATTORI, MICHIHIRO HATTORISearch for more papers by this authorJUN SASAKI, JUN SASAKISearch for more papers by this authorKENJI NUKINA, KENJI NUKINASearch for more papers by this author TSUNETAKA SASAKI, TSUNETAKA SASAKISearch for more papers by this authorMICHIHIRO HATTORI, MICHIHIRO HATTORISearch for more papers by this authorJUN SASAKI, JUN SASAKISearch for more papers by this authorKENJI NUKINA, KENJI NUKINASearch for more papers by this author First published: August 12, 1975 https://doi.org/10.1002/chin.197532096AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume6, Issue32August 12, 1975 RelatedInformation

Studies of Aqueous Sodium Dodecyl Sulfate Solutions by Activity Measurements

Abstract The activities of surfactant ions (aD) and counterions (aNa) were directly obtained by the EMF measurement of a concentration cell with an ion-exchange membrane and by pNa measurements respectively for aqueous solutions of sodium dodecyl sulfate (NaDS) below and above the CMC. The mean activity and activity coefficient were also calculated. From these data, together with the surface tension (γ) measured by the Wilhelmy method and the amount of adsorption (Γ) measured by the radiotracer method, the following results were obtained: (1) Mean activity was not constant, but increased with the concentration above the CMC. (2) The Gibbs adsorption isotherm was directly verified from the aD and aNa vs. concentration relations. (3) The decrease in γ observed above the CMC was in agreement with that calculated from the activity data. (4) The logaD vs. logaNa plots above the CMC showed a linear relation, indicating the validity of the charged phase separation model as the mechanism of micelle formation. The degree of the counterion attachment of the micelles was found to be 0.73 up to about 80 mmol/l. (5) The intermicellar concentrations of Na+ and DS− ions were calculated; the former increases, while the latter decreases with the concentration. (6) The product of the concentration with an osmotic coefficient was linear with the concentration above the CMC, tangent of the slope being about 0.7.

An Equilibrium Study of Reactions Involving a Cationic Surfactant and Various Counterions: Prediction of Ion Selectivity

Abstract The thermodynamic equilibrium constants for the reactions between the cationic surfactant, ethylhexadecyldimethylammonium bromide, EHDA-Br, and various anions were determined using spectrophotometric and specific ion electrode measurements. The sequence of stability of EHDA+ in the presence of the anions X− studied is Br− > F− > H2PO4 − > NO3 − > C6H5O− > I−. The sequence of stability of EHDA-X is the reverse of this. The EHDA+ stability sequence is the same as the order of selectivity expected during foam fractionation from published results for Br−, I−, NO3 −, and for H2PO4 − and C6H5O−, i.e., I− preferred over NO3 −, which is preferred over Br−, etc. The stability and selectivity sequences are interrelated by the steric hindrance of EHDA+ in the presence of the anions X− at the bubble surface.

The application of the thermodynamic theory of ideal multi component micelles to ionic micelles

The thermodynamic theory of ideal multi component micelles is applied to solutions of a single ionic surfactant plus electrolyte with common counterion. It is assumed that the activity coefficients of all micellar species are equal, that counterions can be regarded as bound or free and that non surface active simili-ions are absent from the micelles. Expressions are presented for the free energy, enthalpy and volume changes on micellisation, for the dependence of the latter two on counterion activity and for the individual contribution of surfactant ions and counterions to them. The dependence of the micellar degree of dissociation on counterion and micellar activities is also discussed. The use of an apparent degree of dissociation to incorporate all deviations from ideal behaviour is criticised.

Solubility behavior of water in nonaqueous solutions of oil-soluble surfactants: Effect of molecular structure of surfactants and solvents

The solubility behavior of water in nonaqueous solutions of dialkylsulfosuccinates in varying solvents was studied as a function of temperature. The behavior in cyclohexane solutions of cationic and nonionic surfactants having a similar alkyl group was also studied for comparison with that in solutions of anionic surfactants. Generally, the amount of water solubilized increased markedly over a narrow temperature range, and the nature of turbid regions observed at lower and higher temperatures in the solubility diagrams of the surfactants was opposite to that in the cationic and nonionic surfactant systems. The extent of the solubilization region was anionics > nonionics > cationics. For the anionic surfactant solutions, the solubilization region of water increased with increasing bulkiness of hydrocarbon group of the surfactants, and decreased with increasing valency of surfactant counterion. The longer the alkyl chain length of n-paraffinic solvents and the poorer the solvency for surfactants, the lower was the maximum temperature of solubilization of water. The bulkiness of the hydrocarbon solvent structure as well as that of the surfactant structure played a significant role in the solubilization.