Sodium decyl sulphate

In reverse, the surfactant precipitates from solution as a hydrated crystal at temperatures below 7k, rather than forming micelles. For this reason, below about 20 °C, the micelles precipitate from solution and (being less dense than water) accumulate on the surface of the washing bowl. We say the water and micelle phases are immiscible. The oils re-enter solution when the water is re-heated above the Krafft point, causing the oily scum to peptize. The way the micelle s solubility depends on temperature is depicted in Figure 10.14, which shows a graph of [sodium decyl sulphate] in water (as y ) against temperature (as V). 

Figure 10.14 Graph of [surfactant] (as y ) against T (as V) for sodium decyl sulphate in water. The Krafft temperature is determined as the intersection between the solubility and CMC curves, yielding a /K of about 22 °C. At lower temperatures, the micelles convert to form hydrated crystals, which we might call scum (Reproduced by permission of Wiley Interscience, from The Colloidal Domain by D. Fennell Evans and Hakan Wennerstrom)...

The purpose of this paper is to give a brief summary of an Investigation which has been carried out into the aqueous-phase polymerisation of butadiene initiated by cobalt(III) acetylacetonate In the presence of surfactants such as sodium dodecylbenzene-sulphonate and sodium decyl sulphate. It is Intended that fuller details of the investigation will be published elsewhere in due course. 

N label nematic phase measurements, 7% Na2S04, 36% sodium decyl sulphate, 7% decanol, 50% water, acidified with dilute H2S04 ref. 144. 

Atlasol 103 EINECS 2055655 Sodium decyl sulfate Sodium decyl sulphate Sulfuric acid, decyl ester, sodium salt. Emulsifier, wetting agent, dispersant, fiber lubricant, synthetic fatliquor for textile, leather, and general industrial applications. Atlas Chemical Corp. 

In fact, experimental surface tensions of mixtures of sodium decyl sulphate SDeS (component 1) and sodium dodecyl sulphate SDS (component 2) are described satisfactorily by Eq. (2.48) whereas the application of Eq. (2.51) leads to large differences between theory and experiment [67]. The best agreement between experimental and theoretical values of n was received by using the Frumkin analogue of Eqs. (2.48)-(2.50) with ai=0.7, a2=0.85 and ai2=(ai+a2)/2=0.77. Similarly, mixtures of decyl ammonium chloride and dodecyl ammonium chloride were very well described by these equations with ai=1.2, a2=1.56 and ai2=(ai+a2)/2=1.38 [16]. The latter system also reveals a reverse salting-out effect as an excess of inorganic counterions in the solution increases the adsorption activity of an ionic surfactant, by the same token such an excess in the surface decreases the adsorption activity. As a result, the effect of a second ionic surfactant with a common counterion on the surface pressure is smaller than it would have been according to the additivity rule for non-ionic surfactants expressed in Eq. (2.51). 

The theoretical calculations for the mixture performed with Eq. (3.41) are in perfect agreement with the experimental data. The dependence of surface pressure of aqueous sodium decyl sulphate (CioS04Na) solutions for various additions of Ci2S04Na (without any addition of electrolyte) is shown in Fig. 3.74. 

The theoretical treatment of the model of Aniansson and Wall is not directly applicable to the time constants obtained in ultrasonic experiments, but this gap has been bridged.The amplitude is predicted to be zero at the c.m.c. then increases with concentration to a broad maximum and thence slowly decreases, as observed for sodium dodecyl sulphate. An analysis of amplitudes in P-jump kinetics implies the possibility of a third relaxation process due to a change in electrolyte properties. This counterion binding equilibrium may have been observed in ultrasonic studies of sodium decyl sulphate. Attempts by the former authors to modify the Aniansson and Wall theory... 

Appearance liquid Sodium decyl sulphate Concentration % 40... 

At a particular temperature, the solubility becomes equal to the c.m.c., i.e. the solubility curve intersects the c.m.c. and this temperature is referred to as the KrafFt temperature of the surfactant, which for sodium decyl sulphate is 22 °C. At the KrafFt temperature an equilibrium exists between solid hydrated surfactant, micelles and monomers (i.e. the KrafFt point is a triple-point ). Since the KrafFt boundary represents the region below which crystals separate, the energy of the... 

Figure 9.4(a) Zeta potential as a function of the logarithm of the concentration of anionic surfactants adsorbed on to polystyrene latex sodium tetradecyl sulphate, NaDS, and O sodium decyl sulphate. The CMC for NaDS in water is shown by the arrow, (b) Shows... 

Figure 10.9 Competition of decyl sulphate for decyl glucoside binding sites of bovine serum albumin, (a) Solid curve for decyl glucoside binding as a function of molar mixing ratio of sodium decyl sulphate to bovine serum albumin, (b) Binding of sodium decyl sulphate to bovine serum albumin. From Wasylewski and Kozik [58] with permission.

The electrophoresis technique most often used with proteins is SDS-PAGE, i.e., polyacrylamide gel electrophoresis carried out in the presence of 0.1 % sodium do-decyl sulphate (See and Jackowski 1989). This technique, which was developed by Shapiro, Vinuela and Maizels, separates proteins, or more accurately protein subunits, exclusively on the basis of their molar mass. SDS is an anionic detergent that binds to proteins up to a level of about 1.4 g g 1 of protein, and in so doing it disrupts the quaternary, tertiary and, to a large extent, the secondary structure of the... 

Rudd PM, Colominas C, Royle L, Murphy N, Hart E, Merry AH, Hebestreit HF, Dwek RA. A high-performance liquid chromatography based strategy for rapid, sensitive sequencing of N-linked oligosaccharide modifications to proteins in sodium do-decyl sulphate polyacrylamide electrophoresis gel bands. Proteomics 2001 1 285-294. 

We turn now to the temperature dependence of the cmc. Eqn (6.1) gives little indication of how the cmc should vary with temperature. The observed cmcs all have a minimum between 20-30°C, for sodium n-dodecyl, n-decyl and 2-decyl sulphates, and for n-dodecyl trimethylammonium bromide. While the temperature dependence of the term lyaojkT could be estimated from data on the surface tension of water and decreases with temperature, we have no information on the temperature dependence of the hydrophobic term g—g. However, evidenceon the solubilities and enthalpy of solution of the sequence ethane, propane, butane,... 

Surfactants Ionic, anionic (e.g., sodium dodecyl sulphate, Cj2H250S03 Na ), cationic (e.g., cetyl trimethyl ammonium chloride, Ci,H33-N+(CH3)3C1-), zwitterionic [e.g., 3-dimethyldodecylamine propane sulphonate (betaine CJ2H25-N" (CH3)2-CH2-CH2-CH2-S03)], nonionic, alcohol ethoxylates C H2 +i-0-(CH2-CH2-0) -H, alkyl phenol ethoxylates C H2 +i-CgH4-0-(CH2-CH2-0) -H, amine oxides (e.g., decyl dimethyl amine oxide, C10H21-N ( 113)2 0), and amine ethoxylates. 

Moreover, adsorption isotherms, or equations of state, represent the basis for the evaluation of adsorption kinetics and rheological properties of adsorption layers. Exact equilibrium values of surface or interfacial tensions are necessary to determine adsorption isotherms. For surfactants of low surface activity (for example, sodium octyl or decyl sulphate, hexanol or hexanoic acid) the adsorption reaches its equilibrium state in a time of the order of seconds to minutes. Higher surface activity results in greater times for establishing the equilibrium state of adsorption which sometimes cannot be realised by available experimental methods. To avoid long-time experiments, extrapolations were often carried out in order to get equilibrium values. Different extrapolation procedures as well as criteria of an equilibrium state of adsorption are discussed in the literature (cf Miller Lunkenheimer 1983). 

Mixture of oxyethylated decyl alcohol and sodium dodecyl sulphate in 0.01 M NaCI. 

Several investigations were carried out to study the above transitions from common film to common black film and finally to Newton black film. For sodium do-decyl sulphate, the common black films have thicknesses ranging from 200 nm in very dilute systems to about 5.4 nm. The thickness depends strongly on electrolyte concentration and the stability may be considered to be caused by the secondary minimum in the energy distance curve (see Chapter 7). In cases where the film thins further and overcomes the primary energy maximum, it will fall into the primary minimum potential energy sink, where very thin Newton black films are produced. The transition from common black films to Newton black films occurs at a critical electrolyte concentration that depends on the type of surfactant. 

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