Sodium dodecyl sulphate /water

Fig. 15.5 Long-exposure photographs recorded for argon-saturated water (a) and luminol solution (b) and (c) 10 mM sodium dodecyl sulphate (SDS) solution. The emission spectra in (d) are from pure argon-saturated water and 10 mM SDS solution. Note the sodium D line at 589 nm. In this experiment, sonication was performed at 159 kHz...

Figure 10.12 Micelles of sodium dodecyl sulphate (SDS) comprise as many as 80 monomer units. The micelle interior comprises the hydrocarbon chains, and is oil like. The periphery presented to the water of solution is made up of hydrated hydrophilic sulphonic acid groups...

Figure 3. Phase diagrams of the system water sodium dodecyl sulphate/alkanols benzene (a) ethanol (b) 2-propanol (c) 1-propanol(d) 1-butanol (e) 1-pentanol (f) 1-hexanol (g) 1-heptanol.

Antimony potassium tartrate Sodium dodecyl sulphate Dl water... 

Dissolve 1.8 g of ammonium molybdate in 700 ml of Dl water. Cautiously, while swirling, slowly add 22.3 ml of sulphuric acid. Add 0.05 g antimony potassium tartrate and dilute to 1 I with Dl water. Mix thoroughly and add 2 g of sodium dodecyl sulphate. Store in a dark bottle. Prepare fresh weekly. 

Make two identical surfactant solutions by dissolving 2.5 g sodium dodecyl sulphate (SDS) in lO.Ocm of distilled water at room temperature. (The solution may need to be heated to dissolve the surfactant.) Take care excessive shaking will cause foaming. 

Surfactant (sodium dodecyl sulphate) Distilled water... 

A molecularly imprinted polypyrrole film coating a quartz resonator of a QCM transducer was used for determination of sodium dodecyl sulphate (SDS) [147], Preparation of this film involved galvanostatic polymerization of pyrrole, in the presence of SDS, on the platinum-film-sputtered electrode of a quartz resonator. Typically, a 1-mA current was passed for 1 min through the solution, which was 0.1 mM in pyrrole, 1 mM in SDS and 0.1 M in the TRIS buffer (pH = 9.0). A carbon rod and the Pt-film electrode was used as the cathode and anode, respectively. The SDS template was then removed by rinsing the MlP-film coated Pt electrode with water. The chemosensor response was measured in a differential flow mode, at a flow rate of 1.2 mL min-1, with the TRIS buffer (pH = 9.0) as the reference solution. This response was affected by electropolymerization parameters, such as solution pH, electropolymerization time and monomer concentration. Apparently, electropolymerization of pyrrole at pH = 9.0 resulted in an MIP film featuring high sensitivity of 283.78 Hz per log(conc.) and a very wide linear concentration range of 10 pM to 0.1 mM SDS. 

Surfactant solutions above the c.m.c. can solubilise otherwise insoluble organic material by incorporating it into the interior of the micelles for example, the dye xylenol orange dissolves only sparingly in pure water but gives a deep red solution with sodium dodecyl sulphate present above its c.m.c. 

In general, micellisation is an exothermic process and the c.m.c. increases with increasing temperature (see page 86). This, however, is not universally the case for example, the c.m.c, of sodium dodecyl sulphate in water shows a shallow minimum between about 20°C and 25°C. At lower temperature the enthalpy of micellisation given from equation (4.28) is positive (endothermic), and micellisation is entirely entropy-directed. 

Matijevic, E. and Pethica, B.A. (1958) The properties of ionized monolayers. Part 1. Sodium dodecyl sulphate at the air/water interface. Part 2. The thermodynamics of the ionic double layer of sodium dodecyl sulphate. Trans. Faraday Soc., 54, 1382-99. 

Extraction Solvent. Mix 50 ml of water-saturated isobutyl mediyl ketone with 50 ml of water-saturated isobutanol, and add 0.5 g of sodium dodecyl sulphate. 

Effect of hexadecane as additive In a series of papers Hallworth and Carless (7,8,9,TO) have investigated the effect of the nature oT the internal phase on the stability of oil in water emulsions as well as the effect of addition of long chain fatty alcohols with sodium dodecyl sulphate or sodium hexadecyl sulphate as the ionic emulsifier. They found that light petroleum and chlorobenzene emulsions prepared only with sodium hexadecyl sulphate were much less stable than those produced using the longer chain paraffins, white spirit and light liquid paraffins. 

In another interesting development, Yei et al. [124] prepared POSS-polystyrene/clay nanocomposites using an emulsion polymerization technique. The emulsion polymerization for both the virgin polystyrene and the nano composite started with stirring a suspension of clay in deionized water for 4h at room temperature. A solution of surfactant ammonium salt of cetylpyridinium chloride or POSS was added and the mixture was stirred for another 4 h. Potassium hydroxide and sodium dodecyl sulphate were added into the solution and the temperature was then raised to 50 °C. Styrene monomer and potassium persulfate were later on added slowly to the flask. Polymerization was performed at 50 °C for 8 h. After cooling, 2.5% aqueous aluminium sulphate was added to the polymerized emulsion, followed by dilute hydrochloric acid, with stirring. Finally, acetone was added to break down the emulsion completely. The polymer was washed several times with methanol and distilled water and then dried overnight in a vacuum oven at 80 °C. The obtained nanocomposite was reported to be exfoliated at up to a 3 wt % content of pristine clay relative to the amount of polystyrene. 

The technique involves first producing a seed latex by emulsifier-free emulsion polymerisation. A polystyrene latex of about 1 pva diameter is usually used. The seed particles are initially swollen using a microemulsion of a free radical initiator and a low molecular weight activating solvent , such as dibutyl phthalate, emulsified in water by sonication using sodium dodecyl sulphate as stabiliser. The seed... 

Pure water at a high pressure and temperature was the solvent used as extractant in most applications. However, the addition of a modifier [157,173] or a co-extractant [47] can dramatically improve the extraction of some substances. Such is the case with the extraction of nonylphenol polyethoxy carboxylates from industrial and municipal sludges, where recovery was increased by more than 30% in the presence of 30% (v/v) ethanol in the water used as leaching agent [157]. Because of the hydrophobic nature of PAHs, the increased dielectric constant of water at a high temperature did not suffice to ensure quantitative extraction from soil. However, as can be seen from Fig. 6.14, the addition of a co-extractant (viz. sodium dodecyl sulphate, SDS, which forms charged micelles) dramatically improved the extraction of these hydrophobic compounds also, it substantially reduced the extraction time and enabled the quantitative recovery of benzo(a)-acenaphthene [47]. 

A lot of microemulsions, located on demixing surfaces (At larger alcohol content, inside the 1-phase domain, definite droplets may no longer exist (10) (11)) in the phase diagram (Figure 1) have been studied. For this purpose, the constituents (oil and alcohol), the amount of surfactant or the water salinity have been varied. The surfactant was SDS (sodium dodecyl sulphate). The composition for several microemulsions series is indicated in Table I. 

Shergold. H.L. and Mellgren, O., Concentration of minerals at the oil-water interface Hematite-iso-octane-water system in the presence of sodium dodecyl sulphate, Trans. IMMC, 78, 121, 1969. 

Competitive displacement of spread (3-lactoglobulin from an air-water interface by (a) nonionic and (b) ionic surfactants. The collapse of the protein network is indicated by showing the change in area occupied by the protein at the interface as a function of surface pressure, (a) Data for A-Tween 20 (polyoxyethylene sorbitan monolaurate) and B-Tween 60 (polyoxyethylene sorbitan momostearate). (b) Data for A-cetyl-trimethyl-ammonium bromide (CTAB), B-lyso-phosphatidylcholinelauroyl (LPC-L), and -sodium dodecyl sulphate (SDS). 

The condensation method begins with molecular units, and the particles are built-up by a process of nucleation typical example is the preparation of polymer lattices, in which case the monomer (e.g., styrene or methylmethacrylate) is emulsified in water using an anionic or nonionic surfactant (e.g., sodium dodecyl sulphate or alcohol ethoxylate). A polymeric surfactant is also added to ensure the long-term colloid stabiHty of the resulting latex. An initiator such as potassium persulphate is then added and, when the temperature of the system has increased, initiation occurs that results in formation of the latex [polystyrene or poly(methylmethacrylate)]. 

In the experiments above, water soluble antioxidants such as ascorbic acid and glutathione were added to the reaction solution as an aqueous solution, while P-carotene and a-tocopherol were added as a chloroform solution emulsified with sodium dodecyl sulphate. Electrochemically reduced water was prepared by use of TRIMION TI-8000 (Nihon Trim Inc, Osaka, Japan) fi om water purified by deionization and reverse osmosis, containing 0.02 % NaCl. In the CL measurements in this case, 600 pL of electrochemically reduced water and same volumes of other reagents as above were used, and then total volume of the reaction mixture was adjusted to 1 mL by changing the volume of DIW. 

The self-assembly of amphiphilic molecules in non-aqueous polar solvents is usually attenuated compared to that in water. The CMCs increase significantly upon the substitution of water by polar solvents [2, 57, 58]. For example, the CMC of ionic surfactants in ethylene glycol are two orders of magnitude larger than that in water [57], while the monomeric solubility of sodium dodecyl sulphate in formamide is so high that micelles do not form at all [58]. Attenuation of self-assembly in non-aqueous polar solvents is the result of the reduced free energy of repulsion between polar solvents and the solvent-phobic parts of amphiphiles compared to that in water. 

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