Mass surfactant

It can be fundamentally stated that surfactants covering nearly all tasks can be derived from phosphoric acid. It is often only the somewhat higher price blocking the same widespread use of phosphorus-containing surfactants compared to the output of mass surfactants. The fraction of phosphorus-containing surfactants reaches about 1 % of total surfactant production. 

Ozaki, H. and Terabe, S., On-line micellar electrokinetic chromatography-mass spectrometry with a high molecular-mass surfactant, ]. Chromatogr. A, 794, 317, 1998. 

Low molecular mass surfactants are not needed in an ice cream mix to stabilize the fat emulsion, due to an excess of protein and other amphiphilic molecules in solution. If a mix is homogenized without added surfactants, both the whey proteins and the caseins will form this new fat globule membrane, with the caseins contributing most of the adsorbed protein... 

The equivalent film thickness hw initially decreases and then levels off at a constant value. The plateau starts at a critical electrolyte concentration Cei,cr = 3-1 O 3 mol dm 3 NaCl, similar to low molecular mass surfactants. The increase in bulk copolymer concentration raises the plateau (45 1 nm vs. 39 3 nm), but has no marked influence on the sloped branch. The results for the lower copolymer (P85) are very similar. The equivalent film thickness hw initially decreases and above Ceicr = 3-10 2 mol dm 3 NaCl levels off at a constant value of 17 + 1 nm (Ce , = 7-10 5 mol dm 3 P85). 

Many techniques can be used for the determination of critical association concentrations (CACs), however, not all of them are sensitive enough to detect the onset of aggregation if this occm i at very low concentrations. Since the CACs of block copolymers are usually much lower than those of low molecular mass surfactants [54], we used pyrene as a fluorescent probe and calculated the effective CACs from the changes in the spectral characteristics of pyrene [55] as a function of surfactant concentration. If we represent the intensity of the emission spectra as a function of the block copolymer concentration, we directly obtain C4C, [56]. From the excitation spectra we obtain CACi by representing the ratio /340//335 vs. log C. 

The amphiphilic polymers and copolymers offer broad aspects for applications similar to low molar mass surfactants. Modifications of solutions, e.g. with respect to their viscosity, can be performed by the variation of the degree of polymerization of the polysurfactants easily. The liquid crystalline phase... 

MEKC Using High-Molecular-Mass Surfactants... 

The use of a high-molecular-mass surfactant (HMMS) or polymerized surfactant has been recently investigated as a pseudo-stationary phase in MEKC. Because a HMMS forms a micelle with one molecule, enhanced stability and rigidity of the micelle can be obtained. 

Also, it is expected that the micellar size is controlled easier than with a conventional low-molecular-mass surfactant (EMMS). The first report on enantiomer separation by MEKC using a chiral HMMS appeared in 1994, where poly(sodium A-undecylenyl-L-valinate) [poly(L-SUV)] was used as a chiral micelle and binaphthol and laudanosine were enantioseparated. The optical resolution of 3,5-dinitrobenzoylated amino acid isopropyl esters by MEKC with poly(sodium (10-undecenoyl)-L-valinate) as well as with SDVal, SDAla, and SDThr was also reported. 

Self-assembly in RTILs is not limited to low molar mass surfactants. For example, He et al. [38 ] have reported about spherical micelles in mixtures of poly( (1,2 -butadiene) -block-ethylene oxide) (PB-PEO) diblock copolymers in the RTIL l-butyl-3-methylimidazolium... 

High-molecular mass surfactants such as butyl acrylate-butyl methacrylate-methacrylic acid copolymer sodium salts, starburst dendrimers, poly(amidoamines), and diaminobutane-based poly(propyleneimine) as well as cationic polyelectrolytes (ionenes) had all been presented as successful secondary phases for aromatic compounds. The determination of 10 nitrophenols in glycine buffers modified by 3-CD (0-10 mmolL" ) and polyvinylpyrrolidone (PVP) (0.5-2.5% w/v) is an example of application of polymer-based electrolytes to rain, tap, and process water. ... 

The mininuim requLements for a dispersioi polymerization are monomer, solventAion-solvent, initiator and steric stabilizer. Some workers have championed the use of so-called co-stabilizers, which typically are low molar mass surfactants. The rationale for using these is reviewed in Section 22.4.3.3. 

Cyclodextrins can be added to the run buffers that contain high-mass surfactants. However, these surfactants can interact with the cyclodextrins, reducing the selectivity of the run buffer system and causing a loss in resolution. 

Macromolecular surfactants or high-molecular-mass surfactants (HMMS), butyl acrylate-butyl meth-acrylate-methacrylic acid copolymers (BMMAs), and sodium 10-undecylenate (SUA) oligomer have been introduced as PSs for MEKC. Since a HMMS forms a molecular micelle, which consists of one molecule, and the CMC value is essentially zero, one can expect a higher reproducibility in a HMMS-MEKC system compared with a low molecular mass surfactant (LMMS)-MEKC system. 

MEKC USING HIGH-MOLECULAR-MASS SURFACTANTS... 

Calculate the repulsion between the two surfaces of a drained water film containing 10" M (1 1) electrolyte and having an eqniUbrium thickness of 2.5 mn. The film is stabilized by a low-molecular-mass surfactant. The contribution from dispersion forces may be neglected. The electric potential at the surfaces is 40 mV, the temperature 25°C, and the dielectric constant in the film is 78.5. Consult the theory of Chapter 16. 

To some extent the effect of the salt addition is similar to that observed for analogeous systems with low molecular mass surfactants surfactant is concentrated at the interface resulting in the formation of a middle phases. 

Gelatin (a denatured fibrillar protein collagen) is one of the most widespread natural high molecular mass surfactants in food, cosmetic, pharmaceutical, medicine, photographic industries as well as in the other fields. Addition of a low molecular mass component to gelatin provides the most effective influence on the surfactant properties. It is related to the formation of gelatin-surfactant complexes - a new type of surfactants. 

Three types of surfactants are known (1) electrostatic (anionic or cationic) low-molecular mass surfactants (2) steric stabilizers such as poly(vinyl alcohol), or a combination of (1) and (2) and (3) electrosteric stabilizers such as polyelectrolytes. Furthermore, many other additives (protecting agents, cosolvents, chain transfer agents, buffer systems, etc.) are often necessary. The entire field is reviewed in Ref. [51], comprising the special kinetics of particle growth and formation, particle size, and molecular mass distribution. 

Combination of Polymer with Low Mass Surfactant Molecules. 97... 

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