Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Organized surfactant

The standard electrode potential for zinc reduction (—0.763 V) is much more cathodic than the potential for hydrogen evolution, and the two reactions proceed simultaneously, thereby reducing the electrochemical yield of zinc. Current efficiencies slightly above 90% are achieved in modem plants by careful purification of the electrolyte to bring the concentration of the most harmful impurities, eg, germanium, arsenic, and antimony, down to ca 0.01 mg/L. Addition of organic surfactants (qv) like glue, improves the quaUty of the deposit and the current efficiency. [Pg.174]

Butyl glycol ethers, the largest volume derivatives of -butyl alcohol used ia solvent appHcations (10), are obtained from the reaction of 1-butanol with ethylene oxide. The most important of these derivatives, 2-butoxyethanol, is used principally ia vinyl and acryHc paints as well as ia lacquers and varnishes. It is also employed ia aqueous cleaners to solubilize organic surfactants. 2-Butoxyethanol [111-76-2] has achieved some growth at the expense of the lower alkoxyethanols (ie, methoxy and ethoxyethanol) because of 2-butoxyethanol s lower toxicity. [Pg.358]

AH these mechanisms except high bulk viscosity require a stabilizer in the surface layers of foam films. Accordingly, most theories of antifoaming are based on the replacement or modification of these surface-active stabilizers. This requires defoamers to be yet more surface active most antifoam oils have surface tensions in the 20 to 30 mN/m range whereas most organic surfactant solutions and other aqueous foaming media have surface tensions between 30 and 50 mN/m(= dyn/cm). This is illustrated in Table 3. [Pg.465]

Organic surfactant frequently added to aid wetting and draining. [Pg.527]

MeutralSoluble Salts. So dium sulfate [7757-82-6] and, to a considerably lesser extent, sodium chloride [7647-14-5] are the principal neutral soluble salts used in laundering compositions. They are often considered to be fillers although they perform an important standardizing function enabling the formulator to manufacture powders of a desired, controlled density. Sodium sulfate, in addition, lowers the critical micelle concentration of organic surfactants and thus the concentration at which effective washing can be achieved. [Pg.528]

The removal of dirt and stubborn grease generally requires the use of aqueous-based, heavy-duty industrial cleaners. These cleaners may or may not contain traditional ingredients like caustic or phosphate (which can be replaced by silicates or organic surfactants). [Pg.649]

The exchange of inorganic cations by organic surfactant ions in the clay galleries not only makes the organoclay surface compatible with monomer or polymer matrix, but also de-... [Pg.656]

Figure 1.2 September 2007 cover of a leading international chemistry journal dedicated to sol-gel materials shows mesostructured silicas derived from the cooperative assembly of soluble sol-gel precursors and organic surfactant molecules. (Reproduced from acs.org, with permission.)... Figure 1.2 September 2007 cover of a leading international chemistry journal dedicated to sol-gel materials shows mesostructured silicas derived from the cooperative assembly of soluble sol-gel precursors and organic surfactant molecules. (Reproduced from acs.org, with permission.)...
Organic surfactants tend to accumulate in biological membranes due to their lipophilic alkyl chains and their affinity for interfaces. Through this characteristic, organisms are capable of concentrating surfactants. Surfactants of all classes are readily taken up across gills [1]. Therefore, it is important to dispose of techniques that make it possible to extract and quantify the analyte in biological tissues and media. [Pg.458]

Interest in the nature of interactions between shortchain organic surfactants and large molecular weight macromolecules and ions with hydroxyapatite extends to several fields. In the area of carles prevention and control, surfactant adsorption plays an important role in the Initial states of plaque formation (1-5) and in the adhesion of tooth restorative materials ( ). Interaction of hydroxyapatite with polypeptides in human urine is important in human biology as hydroxyapatite has been found as a major or minor component in a majority of kidney stones ( 7). Hydroxyapatite is used in column chromatography as a material for separating proteins (8-9). The flotation separation of apatite from... [Pg.311]

Only a few systematic studies have been carried out on the mechanism of interaction of organic surfactants and macromolecules. Mishra et al. (12) studied the effect of sulfonates (dodecyl), carboxylic acids (oleic and tridecanoic), and amines (dodecyl and dodecyltrimethyl) on the electrophoretic mobility of hydroxyapatite. Vogel et al. (13) studied the release of phosphate and calcium ions during the adsorption of benzene polycarboxylic acids onto apatite. Jurlaanse et al.(14) also observed a similar release of calcium and phosphate ions during the adsorption of polypeptides on dental enamel. Adsorption of polyphosphonate on hydroxyapatite and the associated release of phosphate ions was investigated by Rawls et al. (15). They found that phosphate ions were released into solution in amounts exceeding the quantity of phosphonate adsorbed. [Pg.312]

The fluidity (nanoviscosity) in an organized surfactant assembly on soUds can be substantially different from that in the bulk aqueous phase and hence, the diffusional resistance experienced by the probe in the micelle will be considerably different from that faced in the bulk solution [ 145]. Measurement of the viscosity or fluidity of the interior of a micelle is based on measurement of fluorescence properties that depend on the mobihty of the probe in the interior. A commonly used method for such studies involves the intramoleciflar... [Pg.181]

When a polymer film is used as a substrate, aqueous Ti02 paste without organic surfactants is sintered at relatively low temperatures, with approximately 150°C being sufficient to produce mechanically stable 2 films. Sommeling et al. at ECN used an ITO-coated polyethylene terephthalate) (PET) film as a substrate and prepared a plastic DSSC [164-167]. A cell performance with a 7 of 15 pA/cm2, Voc of 0.48 V, and ff of 0.67 was obtained at an illumination intensity of 250 lux. This performance is sufficient for a power supply for indoor applications such as watches and calculators. Under AM 1.5 irradiation, a Vtx of 0.7 V and /sc of 2 mA/cm2 were obtained. [Pg.162]

Even closer to cell membranes than monolayers and bilayers are organized surfactant structures called black lipid membranes (BLMs). Their formation is very much like that of an ordinary soap bubble, except that different phases are involved. In a bubble, a thin film of water — stabilized by surfactants — separates two air masses. In BLMs an organic solution of lipid forms a thin film between two portions of aqueous solution. As the film drains and thins, it first shows interference colors but eventually appears black when it reaches bilayer thickness. The actual thickness of the BLM can be monitored optically as a function of experimental conditions. Since these films are relatively unstable, they are generally small in area and may be formed by simply brushing the lipid solution across a pinhole in a partition separating two portions of aqueous solution. [Pg.397]


See other pages where Organized surfactant is mentioned: [Pg.9]    [Pg.240]    [Pg.526]    [Pg.526]    [Pg.526]    [Pg.526]    [Pg.526]    [Pg.526]    [Pg.526]    [Pg.527]    [Pg.537]    [Pg.908]    [Pg.618]    [Pg.663]    [Pg.586]    [Pg.266]    [Pg.542]    [Pg.229]    [Pg.333]    [Pg.398]    [Pg.111]    [Pg.331]    [Pg.335]    [Pg.19]    [Pg.244]    [Pg.135]    [Pg.24]    [Pg.107]    [Pg.209]    [Pg.136]    [Pg.148]    [Pg.236]    [Pg.410]    [Pg.805]   


SEARCH



Adsorption of Model Organic Compounds on Surfactant Treated Cellulose Fibres

Organic solutes, surfactants

Organic solvents, nonionic surfactant

Organic solvents, nonionic surfactant micelles

Organic surfactant molecule

Organic surfactants

Organic surfactants

Organized assemblies formed from organic surfactant

Organized surfactant assemblies

Organized surfactant systems

Self-Organized Surfactant Structures. Edited by Tharwat F, Tadros

Self-Organized Surfactant Structures. Edited by Tharwat F, Tadros 2010 WILEY-VCH Verlag GmbH Co. KGaA, Weinheim

Structure of Nonionic Surfactant Micelles in Organic Solvents A SAXS Study

Surfactant organisms

Surfactant organization

Surfactant organization

Surfactant, Water, and Organic Material Ternary Systems

Surfactant-Assisted Precipitation of Inorganic-Organic Hybrid Phases

Surfactants in organic

Surfactants in organic solvents

Surfactants silicon-organic

The Organic Chemistry of Surfactants

© 2024 chempedia.info