Anionic-nonionic surfactant systems solubilization

In this paper, we report the solution properties of sodium dodecyl sulfate (SDS)-alkyl poly(oxyethylene) ether (CjjPOEjj) mixed systems with addition of azo oil dyes (4-NH2, 4-OH). The 4-NH2 dye interacts with anionic surfactants such as SDS (11,12), while 4-OH dye Interacts with nonionic surfactants such as C jPOEn (13). However, 4-NH2 is dependent on the molecular characteristics of the nonionic surfactant in the anlonlc-nonlonic mixed surfactant systems, while in the case of 4-OH, the fading phenomena of the dye is observed in the solubilized solution. This fading rate is dependent on the molecular characteristics of nonionic surfactant as well as mixed micelle formation. We discuss the differences in solution properles of azo oil dyes in the different mixed surfactant systems. 

It appears that for each snrfactant system, AG° is a linear fnnction of the number of carbon atoms of the solubihzate see, for example, the work by DeLisi and co-workers who have stndied alcohol solubilization in SDS, dodecyltrimethylammonium bromide, and dodecyldimethylamine oxide.In this work we prefer to plot AG" as a fimction of the niunber of CH2 groups of the solubilizate. Tables 6.2 through 6.6 contain data for several homologous series in anionic, cationic, and nonionic surfactants, and on this basis the following relationship has been tested ... 

IV. Detergents are surface active substances that have features of all three surfactant groups described above, and in addition they are able to spontaneously form thermodynamically stable colloidal systems (for micellization in surfactant solutions please refer to Chapter VI). The particles that are washed away may become incorporated into the nuclei or micelles, i.e. solubilization (See Chapter VI) takes place. Various anionic, cationic, and nonionic surfactants that are encountered further in this section are typically members of this surfactant group. 

Hild to the skin. Compatible with anionic, cationic and nonionic surfactants. Excellent viscosity builder and gelling agent. Hard-water tolerance permits equally good foaming in hard and soft water. Stable in high-electrolyte solutions and will help solubilize other surfactants into these systems. Stable in acidic and alkaline conditions, functioning as cationic in acid media and as anionic in alkaline. Lime soap dispersant. 

Using steady-state absorption studies, several other authors examined the micropolarity of confined IL in microemulsions stabilized by ionic surfactants [64,85,87], For example, Sarkar and coworkers examined [bmim][BF ]/benzene mixtures stabilized by the anionic SAIL surfactant [bmim][AOT] and observed that, within the studied range, the A for solubilized MO continued to undergo redshift with increasing R [85, 87], In another work, Falcone and coworkers compared the micropolarities of [bmim][BF4]/benzene mixtures stabilized by cationic BHDC and nonionic TX-lOO surfactants using l-methyl-8-oxyquinolinium betaine (QB), a dye that locates mainly at the surfactant interfacial layer [64]. When [bmim][BF ] was added to both BHDC/benzene and TX-lOO/benzene systems, a larger hypsochromic shift was sensed by the probe in the former. This implies that the local environments in BHDC/benzene system are more polar. The authors ascribed this phenomenon to the strong electrostatic interactions between the [BFJ anion and the BHD moiety of the cationic surfactant. 

Problems arising from surfactant systems are twofold. The more serious one involves base malodors which often can be traced to very low levels of (low-molecular-weight) fatty acids or alcohols. Intense fatty notes from firee alcohol in ethoxylated fatty alcohols can be very troublesome. The second feature is that improvements to the fat-solubilizing power of the surfactant system will tend to result in higher levels of perfume solubilization with resulting lower cloth deposition. Base malodors are always best tackled at the source and a perfumer can readily advise which malodor he can more easily cope with when asked. Suppliers of surfactants can sometimes modify their process or product specification to accommodate matters the narrow-cut ethoxylates and the processes of topping and tailing nonionic ethoxylates are examples of this. In situ neutralization of adds to form anionics such as sodium dodecylbenzene sulfonate and the consequent possibility of (localized products) extreme pH were referred to in Sec. IV.A. 

In recent studies, Friberg and co-workers (J, 2) showed that the 21 carbon dicarboxylic acid 5(6)-carboxyl-4-hexyl-2-cyclohexene-1-yl octanoic acid (C21-DA, see Figure 1) exhibited hydrotropic or solubilizing properties in the multicomponent system(s) sodium octanoate (decanoate)/n-octanol/C2i-DA aqueous disodium salt solutions. Hydrotropic action was observed in dilute solutions even at concentrations below the critical micelle concentration (CMC) of the alkanoate. Such action was also observed in concentrates containing pure nonionic and anionic surfactants and C21-DA salt. The function of the hydrotrope was to retard formation of a more ordered structure or mesophase (liquid crystalline phase). 

An example of surfactant behavior in conventional liquid solvents is shown in Fig. 3 for the nonionic C12EO5-water-heptane system [12]. The upper boundary of the narrow one-phase region, shown by open circles, is the solubilization boundary. The lower boundary, shown by filled circles, is the haze point curve. AOT systems have the same kind of phase behavior, but since AOT is anionic the relative positions of the solubilization and haze point... 

Uses Hydrotrope for nonionic and anionic surfactants in alkaline and acid systems, low-foam, high-pressure detergents solubilizer for water disp. nonionics Features Low-foaming improved acid stability Regulatery DOT nonregulated... 

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