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Journal ArticleDOI

On the Relation between Viscosity and Critical Micelle Concentration of Detergent Solutions

01 Apr 1953-Bulletin of the Chemical Society of Japan (The Chemical Society of Japan 公益社団法人 日本化学会)-Vol. 26, Iss: 4, pp 177-183
TL;DR: In this paper, a new method for determining 1st CMC from viscosity is experimentally established, and a method of determining 2nd CMC was established by transforming and viscousity in the new variables.
Abstract: (1) Several methods of determining CMC are compared and criticised. (2) A new method of determining 1st CMC from viscosity is experimentally established. (3) A new method of determining 2nd CMC from viscosity is established by transforming and viscosity in the new variables. (4) Of each soap, characteristic constants [η1] and [η2] are discovered, and it is shown that a definite relation is concluded between these values and monomer molecular weight. (5) The theoretical explanation of these newly found phenomena has not yet been made.
Citations
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Journal ArticleDOI
TL;DR: In this article, it was shown that a considerable share of the different micellar phases that potentially exist in surfactant solutions can be formed with a single perfluoro-surfactant by adding different additives to the same starting solution.

103 citations

Journal ArticleDOI
TL;DR: In this paper, the relative kinematic viscosity of aqueous solutions of dodecyldimethylammonium chloride in the presence of NaCl of different concentrations has been measured by an Ubbelohde-type capillary viscometer having four bulbs of successive heights.

86 citations

Journal ArticleDOI
TL;DR: In this paper, the 2nd critical micelle concentration (CMC) exists in addition to the 1st CMC and is greatly influenced by such additives as sodium chloride, dodecyl alcohol, and benzene; these results are in good agreement with those obtained from the conductivity measurements described in the previous paper.
Abstract: Our viscosity and density studies of an aqueous solution of sodium dodecyl sulfate have revealed that the 2nd critical micelle concentration (CMC) exists in addition to the 1st CMC and that the 2nd CMC is greatly influenced by such additives as sodium chloride, dodecyl alcohol, and benzene; these results are in good agreement with those obtained from the conductivity measurements described in the previous paper. The reduced viscosity of the micelle (ηsp.m/Cm) vs. Cm curve showed a knick at the concentration corresponding to the 2nd CMC as obtained by Tyuzyo and his co-workers. The molar volume of the hydrated micelle was calculated by using the equation: ηr.m=1+2.5φm+14.1φm2; it has been found to decrease at about the 2nd CMC, similarly to the partial specific volume (\barv) of SDS obtained from the density measurement. This may be attributed to a change in the micelle structure at the 2nd CMC, caused by a variation in the type of aggregation and by a decrease in the counter-ion binding by the micelle.

67 citations

Journal ArticleDOI
TL;DR: The influence of excess NaCl on the properties of viscoelastic detergent solutions of Cetypyridiniumsalicylate (CPySal) has been studied by static and dynamic light scattering, electric birefringence and rheological measurements.

57 citations

Journal ArticleDOI
TL;DR: In this paper, a modified version of the Onsager equation, based on stepwise association model, is presented, which produces discontinuities in the solutipn-vapor interfacial tension vs. concentration curve.
Abstract: The subject of pre- and postmicellar association is reviewed. Conductivity- and surface-tension results (in conjunction with literature data) show that each homolog of the sodium fatty-acid soap series has at least three definite association concentrations, collectively termed “multi-CMC”. Hydrolysis of the soaps was shown to be compatible with association and to vary with it. The variation of the equivalent conductivity with concentration is discussed theoretically, the former shown to increase with premicellar association. A modified version of theOnsager equation, based on stepwise association model, is presented. Theory and experiment were in good agreement. Stepwise bulk association produces discontinuities in the solutipn-vapor interfacial tension vs. concentration curve. The discontinuity points coincide with the defined CMC's. The enthalpy of micellization is of the same order for all CMC points, with the peak corresponding to the conventional CMC. At least three sets of log CMC vs. chain length relations are defined for theC 8-C 18 homologs of the sodium fatty-acid soap series. The above results, in conjunction with reinterpreted' literature data, suggest that association is discontinuous, and that there is a central CMC with secondary association concentrations distributed on both sides. Die vorliegende Ubersicht behandelt vor- und nachmicellare Assoziation. Ergebnisse von Leitfahigkeits-und Oberflachenspannungsmessungen zusammen mit Angaben aus der Literatur deuten darauf hin, das jedes Glied der Fettsaurenreihe mindestens drei bestimmte Assoziationskonzentrationen aufweist, eine Tatsache, welche allgemein mit vielfacher kritischer Micellen-(Assoziationskolloid-)Konzentration (KMK) bezeichnet wird. Hydrolysierung der Seifen konnte als mit der Assoziation vereinbart und als mit dieser veranderlich gezeigt werden. Die Veranderung der aquivalenten Leitfahigkeit in Abhangigkeit von der Konzentration wird theoretisch behandelt, wobei sich ergibt, das die Leitfahigkeit mit der vormizellarischen Assoziation ansteigt. Eine auf dem schrittweisen Assoziationsmodell beruhende abgeanderte Form derOnsagerschen Gleichung wird aufgestellt. Theorie und Versuchsergebnisse stimmen gut uberein. Die stufenweise Massenassoziation fuhrt zu Ungleichformigkeiten in der Kurve der Zwischenschichtspannung Losung-Dampf in Abhangigkeit von der Konzentration, wobei die Unterbrechungsorte mit den angegebenen KMK ubereinstimmen. Die Enthalpie der Micellenbildung hat die gleiche Grosenordnung an allen KMK-Punkten, und das Maximum entspricht der herkommlichen KMK. Mindestens drei Gruppen von Verhaltnissen zwischen log KMK und Kettenlange werden fur die Glieder vonC 8 bisC 18 der Natrium-Fettsaure-Seifenreihe definiert. Die obengenannten Ergebnisse, im Zusammenhang mit den neu gedeuteten Literaturangaben, weisen darauf hin, das Assoziation kein kontinuierlicher Vorgang ist, sowie, das eine mittlere KMK mit sekundaren beiderseits verteilten Assoziationskonzentrationen vorliegt.

56 citations

References
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Journal ArticleDOI
P. Debye1
TL;DR: Soap solutions exhibit even lower osmotic activity than would be predicted if one assumed that soap existed in solution as simple undissociated molecules, and cryoscopic evidence of micelle formation in aqueous solutions of severa1 non-ionic detergents is obtained.
Abstract: Soap solutions exhibit even lower osmotic activity than would be predicted if one assumed that soap existed in solution as simple undissociated molecules. Soap solutions alço conduct the electric current far better than would be expected from the observed osmotic effects. Attempting to explain these anomalies, McBain,' in 1913, suggested that the fatty soap ions aggregated in solution. Such colloidal aggregations of ions, which were termed micelles, would explain the low osmotic activity and relatively high conductivity of soap solutions. Since 1913, investigators have shown considerable interest in the determination of the size and shape of the micelle. McBainP proposed two different rnicelle species, which he said could coexist in solution: one a small, spherical, hydrated, ionic micelle, and the other a large, larnellar, weakly conducting micelle. While agreeing with McBain that the behavior of soap solutions pointed to the existence of micelles, Hartleya took the view that only the small spherical micelle was feasièle. On the basis of geometrical considerations, Hartley4 calculated that the micelle of a 16 carbon soap consisted of approximately 50 cetyl chains. He and Runnicles5 carried out diffusion experiments with cetyl pyridinium chloride and calculated from their results that the micelle of this soap contained about 70 paraffin chains. Ultracentrifuge and diffusion measurements by Miller and Andersson' on Duponal (sodium salts of sulfated aliphatic alcohols of chain length C S to C,,) led to a molecular weight of 12,500 for the mixed micelle. Hakala' has made diff usion measurements on sodium dodecyl sulfate solutions. If a spherical model for the micelle is assumed, the introdgction of his results into the Stokes-Einstein equation gives a value of 23.6 A for the radius. A molecular weight of about 25,000 (87 paraffin chains per micelle) is obtained from this value of the radius if a density equal to that of dodecane is taken. Vetter' studied the sodium salt of sulfonated di (2-hexyl) succinate, known commercially as Aerosol MA, and from density, viscosity, and diffusion data calculated an aggregation number of 24 for the micelle. Gonick and McBain' obtained cryoscopic evidence of micelle formation in aqueous solutions of severa1 non-ionic detergents. Assuming ideal behavior, their data indicate that a micelle consists of no more than 7 detergent molecules.

190 citations

Journal ArticleDOI
TL;DR: For a homologous series, the volume of oil solubilized at a constant temperature is to a first approximation inversely proportional to the molar volume as discussed by the authors, where m is the number of micelles in the solution.
Abstract: Increase in the concentration of a soap or other detergent does not increase the solubility of an oil above that in water until the critical concentration for the formation of micelles (cmc) is attained. Above this the solubility, designated as solubilization, increases and, in general, more rapidly as the soap concentration increases; i.e., per mole of soap the solubilization is greater in a 25 percent than in a 5 percent soap solution. For a homologous series the volume of oil solubilized at a constant temperature is to a first approximation inversely proportional to the molar volume. The polarity and shape of the molecules solubilized also play a role. Salts increase the extent of the solubilization; at low concentrations to an extent which may be accounted for by the increase in micellar area resulting from the depression of the cmc by the salt. At higher soap concentrations the increase in solubilization is greater than can be accounted for in this way.

73 citations