Surfactant mixing ratio

Izquierdo, P., Feng, J., Esquena, J.,Tadros, T.F., Dederen, J.C., Garcia, M.J., Azemar, N. and Solans, C. (2005) The influence of surfactant mixing ratio on nano-emulsion formation by the PIT method. Journal of Colloid and Interface Science, 285 (1), 388-394. 

Figure 13 Relative self-diffusion coefficients of water and oil as a function of the surfactant mixing ratio in a five-component microemulsion consisting of Ri20CH2CH2S04Cai/2-/-R80CH2CH(0H)CH20H-water with 8 wt% CaCh and decane. Here R12 refers to a dodecyl (C12H25) chain and /-Rg to an isooctyl ((CHj)jC(CH2)4] chain. The system is tuned by the surfactant mixing ratio (Data taken from Ref 47.)...

FIG. 2 Krafft points 7" of hqucous surfactant solutions vs. mixing ratio of c16/c, a-ester sulfonates. (From Ref. 58.)... 

Surface Activity. It is obvious from the J -log C plots (F ig.1 and 2) that the addition of alkyl alcohol results in lowering both the surface tension and, the cmc. In particular, it is worth noting that the surface tension of the mixed solution at cmc,7cme, is significantly lower than the surface tension at the pure surfactant cmc. Cmc and 7cwic of 111 (molar ratio) RDH-Surfactant mixed systems were shown in Table 1. Tcmc RDH-CyFNa solution reaches... 

The sol-pillared clay was prepared following the procedures of Yamanaka et al (1). The mixing ratio of Afsi (mol)/A/T,(moI)/CEC equivalent of clay was 30/3/1. SiC -TiCh sol pillared montmorillonite, subjected to a calcination for 4h at 773 K, was labeled as sol-PILM. Portions of the wet cake prepared with bentonite were subjected to SCD or treatment with surfactants as described below. 

In addition to the surfactant and epoxy resin, the parameters of the emulsification process will significantly influence the properties of the final emulsion. To obtain the smallest achievable droplet size with a narrow droplet size distribution, it is essential to optimize process parameters such as temperature of emulsification and mix ratio of surfactants when more than one surfactant is used. 

Shinoda and Kuineda [8] highlighted the effect of temperature on the phase behavior of systems formulated with two surfactants and introduced the concept of the phase inversion temperature (PIT) or the so-called HLB temperature. They described the recommended formulation conditions to produce MEs with surfactant concentration of about 5-10% w/w being (a) the optimum HLB or PIT of a surfactant (b) the optimum mixing ratio of surfactants, that is, the HLB or PIT of the mixture and (c) the optimum temperature for a given nonionic surfactant. They concluded that (a) the closer the HLBs of the two surfactants, the larger the cosolubilization of the two immiscible phases (b) the larger the size of the solubilizer, the more efficient the solubilisation process and (c) mixtures of ionic and nonionic surfactants are more resistant to temperature changes than nonionic surfactants alone. 

Phase Behavior. The use of phase-behavior diagrams in surfactant-enhanced alkaline flooding is more complicated than in micellar-polymer flooding for several reasons. One reason is that phase behavior is very sensitive to the water-to-oil ratio employed. From surfactant mixing rules, varying the amount of oil present will vary the amount of petroleum soap... 

Interactions between oppositely charged micelles in aqueous solutions spontaneously form vesicles. The self-diffusion coefficient of water and 2H relaxation of 2H-labeled dodecyl trimethyl ammonium chloride of the dodecyl trimethyl ammonium chloride-sodium dodecyl benzenesulfonate systems show that in these mixtures there is limited growth of the micelles with changes in composition. The vesicles abruptly begin to form at a characteristic mixing ratio of the two surfactants. The transition is continuous.205 Transformation from micelle to vesicle in dodecyl trimethyl ammonium chloride-sodium perfluoro-nonanoate aqueous solution has been studied by self-diffusion coefficient measurements, and it was found that at a concentration of 35 wt% with a molar ratio of 1 1, the self-diffusion coefficient of the mixed micelles is far smaller than that of the two individual micelles.206 The characteristics of mixed surfactant... 

The mixing ratio of surfactants should be such that it produces an optimum HLB value for the mixture. 

Ryoo[189] found that the structural order of MCM-41 can be improved remarkably if mixed surfactants of n-alkyltriethylammonium bromides (CrcTEAB, n = 12,14,16,20 and 22), and n-alkyltrimethylammonium bromides (CrcTMAB) are used. The optimum mixing ratio can be tuned according to the length of the alkyl groups. 

T3.8.2.3 Obtained in Microemulsion Ammonium hydroxide was added to a solution containing Igepal Co520 (surfactant) and cyclohexane, and the mixture was shaken to obtain a microemulsion. Solutions of zirconium n-propoxide in acetylacetone and n-butanol (l 0.5 3) and of tetraethyl orthosilicate in water and ethanol (1 1 4) were mixed for 3 h, and the mixture was added to the microemulsion with stirring, and hydrolyzed for 3 d. The final concentrations of alkoxides were 0.0075 M, the water surfactant molar ratio was 0.8, and the water alkoxide molar ratio was 10. The powder was washed with acetone and heated at 900°C for 2 h. 

Compare this with the similar, but not quite identical treatment of the solubility of a drug in a mixed surfactant system, in chapters 4 and 5. Experimental domains defined in this way, by ratios or by mixed ratios and absolute limits may also be treated by the multicomponent constraints method (see chapter 10). 

Finally, very large effects on adsorption and surface pressure have been described for mixtures of anionic RX (R X ) and cationic RY (R Y ) surfactants in the solution. In such systems, the adsorption is represented almost completely by the equimolar composition R R which has a very high surface activity without any noticeable contribution of R"X and R Y over a large rage of mixing ratios [76]. Thus one can describe the surface tension of this mixture for ideal surface layers without any consideration of the DEL influence by... 

ABSTRACT The seam water injection is one of the coal dust prevention measures. However, due to the hydrophobic coal, the wetting effect of clean water is not ideal. By adding manner of the single surfactant and the two surfactants mixed in the water, the surface tension of the solution and the contact angle of 3 groups of coal samples were measured in this article. The experimental results show that two formulations, Pj Fatty alcohol amide with Alkyl quaternary ammonium salt ratio of 2 1 P JFC with Triton X-100 at a ratio of 1 1. 

The liquid gelators, Span 80-Tween 80 also forms emulsion organogels and emulsion hydrogels by fluid-filled fiber mechanism. It has been reported that Span 80 (sorbitan monooleate) and Tween 80 (polyoxyethylene sorbitan monooleate) mixed in the ratio of 1 2 w/w forms organogel with better firmness and architecture as compared to the other surfactant mixture ratios.When water is added dropwise into the homogenous surfactant mixture and oil, it forms spherical reverse-micellar droplets. These droplets/fibers self-assemble to form three-dimensional architecture to immobilize apolar solvent. " Similarly, in case of hydrogels micellar structures are formed, which entraps the external liquid phase to flow and form hydrogel. 

Table 4.3 Ratio of complex formation obatined by mixing and grinding the component crystals of aromatic compounds with heteroatoms and the cationic surfactants. The ratios were calculated using the peak heights of the low-angle diffractions of their X-ray powder patterns...

Two reverse microemulsions containing AOT/isooctane/aqueous solution of zinc nitrate and AOT/isooctane/aqueous solution of sodium sulfide were mixed by Hirai etal [375] for obtaining ZnS. The water/surfactant molar ratio was varied in the range 3-10. With the ratio at 6, the particle diameter was found to increase from about 2.4 nm to about 3 nm as a function of time (up to 100s). This increase was found to be restricted by the micellar size. In a similar work by the same group [358], the particle diameter was demonstrated to increase as a function of water/surf actant molar ratio from about 3.1 nm (w — 4) to 3.7 nm (w = 7.5-10). At w > 10, excessive agglomeration was noted. 

---