Nonionic surfactant definition

With phenanthrene, some indirect evidence for this supposition was demonstrated by adding 100 and 200 mg of glucose (0.13 and 0.25%, w/v) to several phenanthrene and soil-water systems without surfactant to assess whether the presence of a readily degradable substrate would suppress phenanthrene mineralization. In both cases a significant lag period was evident prior to the onset of phenanthrene mineralization. Although not a definitive experiment, this test and the results with nonionic surfactants and phenanthrene (52) and with hexachlorobenzene (66) indicate the need for further investigation. 

Nonionic surfactants are amphiphilic compounds the lyophilic (in particular hydrophilic) part of which does not dissociate into ions and hence has no charge. However, there are nonionics, for example such as tertiary amine oxides, which are able to acquire a charge depending on the pH value. Even polyethers, such as polyethylene oxides, are protonated under acidic conditions and exist in cationic form. Long-chain carboxylic acids are nonionic under neutral and acidic conditions whereas they are anionics under basic conditions. So, the more accurate definition is as follows nonionics are surfactants that have no charge in the predominant working range of pH. The main part of nonionics can be classified into alcohols, polyethers, esters, or their combinations. 

The definition of Gibbs elasticity given by Eq. (19) corresponds to an instantaneous (Aft t ) dilatation of the adsorption layer (that contributes to o ) without affecting the diffuse layer and o. The dependence of o on Ty for nonionic surfactants is the same as the dependence of o on Ty for ionic surfactants, cf Eqs (7) and (19). Equations (8) and (20) then show that the expressions for Eq in Table 2 are valid for both nonionic and ionic siufactants. The effect of the surface electric potential on the Gibbs elasticity Eq of an ionic adsorption monolayer is implicit, through the equilibrium siufactant adsorption T y which depends on the electric properties of the interface. To illustrate this let us consider the case of Langmuir adsorption isotherm for an ionic surfactant (17) ... 

We consider the partitioning of one species to the interface between two phases a and fi) containing several species / in different amounts This procedure will lead to a relationship between the surface tension and concentration for a surfactant, i.e. in this particular case we consider the excess of nonionic surfactant at the air-water interface. It is assumed that the interface can be described by a plane, which is only an approximation because the accumulation of a component (for example surfactant) at the interface leads to a layer of finite thickness. Furthermore, such a layer can alter the structure of the adjacent phases due, for example, to dipole-dipole interactions. There is thus some arbitrariness in the definition of the interfacial plane, but nonetheless we shall see shortly that a convenient choice presents itself. 

The mixed surfactant model could be generalised if a better definition of the surfactants present in the nSOW system could be foimd. The location of the nonionic surfactant during the different stages of phase inversion is also important. 

The signs of the curvature H and the bending moment Bo are a matter of convention. In the present consideration we accept that positive is the curvature of an oil droplet in water. However, the sign of the product BoH (and fV ) is independent of the choice of definition (see e.g. ref. 27). In the case considered above, <0 for aqueous droplets in oil, whereas fV >0 for oil droplets in water. The bending energy contribution can vary with variation in the experimental conditions (electrolyte concentration for ionic surfactants or temperature for nonionic surfactants). 

Corresponding to this definition, the analytical methods are designed to cover intact anionic and nonionic surfactants. 

The family of surfactants commonly referred to as amphoterics are surface-active materials that contain, or have the potential to form, both positive and negative functional groups under specified conditions. Their definition as a separate class of surfactants has historically been somewhat controversial, since they may be electrically neutral and their general properties under many conditions make them functionally similar to some nonionic surfactants. For purposes of discussions related to chemical structures, however, they have been separated into a distinct family. In the final analysis, a surfactant by any other name is still a surfactant, so that too much importance should not be placed on nomenclature. 

Whereas the water-surfactant association implied by N-w/eo is usually considered to be rather weak [11], the existence of definite stable hydrates was shown for the polyoxyethylene-water system [46] and for some (nonionic) surfactant-water systems [47-49]. It was, however, argued that if the phase diagrams of these surfactant-based systems included the putative hydrates, the phase rule would be violated [50]. Clearly, this issue merits further investigation. 

The rate constants for the reaction of a pyridinium Ion with cyanide have been measured in both a cationic and nonlonic oil in water microemulsion as a function of water content. There is no effect of added salt on the reaction rate in the cationic system, but a substantial effect of ionic strength on the rate as observed in the nonionic system. Estimates of the ionic strength in the "Stern layer" of the cationic microemulsion have been employed to correct the rate constants in the nonlonic system and calculate effective surface potentials. The ion-exchange (IE) model, which assumes that reaction occurs in the Stern layer and that the nucleophile concentration is determined by an ion-exchange equilibrium with the surfactant counterion, has been applied to the data. The results, although not definitive because of the ionic strength dependence, indicate that the IE model may not provide the best description of this reaction system. 

Definition Mixture of oleate esters of sorbitol and sorbitol anhydrides, with 20 moles ethylene oxide Properties HLB 11.0 nonionic Toxicology Human skin irritant TSCA listed Uses Surfactant, emulsifier, solubilizer for polymerization, cosmetics, phamfiaceuticals, agric., textiles, paints, pulp/paper, metalworking plastics solubilizer for perfume, flavors, essential oils food emulsifier, stabilizer lubricant antistat vise, modifier suspending agent emulsifier in food pkg. 

CAS 66455-17-2 68551-08-6 EINECS/ELINCS 266-367-6 271-360-6 Synonyms Alcohols, C9-11 Definition Mixture of synthetic fatty alcohols with 9 to 11 carbons in alkyl chain Properties Nonionic Toxicology TSCA listed Uses Surfactant intermediate emollient, emulsion stabilizer, vise, control agent in cosmetics... 

Definition PEG ether of cetearyl alcohol Formula R(OCH2CH2)nOH, R = blend of cetyl and stearyl radicals, avg. n = 17 Properties Nonionic Toxicology TSCA listed Uses Surfactant, emulsifier in cosmetics in food-contact textiles Regulatory FDA 21CFR 177.2800 Trade Name Synonyms G-70147 t[Uniqema Uniqema Am. http //www.uniqema.com]] Procol CS-17 t[Protameen http //www.protameen.com]... 

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