Mixed monolayer and mixed micelle formation in binary mixture of surfactants—Systems for trioxyethylenated dodecyl sulfonate and some polyoxyethylenated fatty alcohol ether nonionic surfactants

Abstract

The interaction and synergism of some polyoxyethylenated fatty alcohol ether (POE) nonionic surfactants (C 12 E 2 , C 12 E 3 , C 10 E 5 , C 10 E 7 , where C x indicates number of carbon atoms in the chain and E y indicates number of oxyethylene glycol ethers) with trioxyethylenated dodecyl sulfonate (C 12 E 3 S) in mixed monolayer formation at the surface and in mixed micelle formation in aqueous solutions were studied at 25 and 40°C by calculating interaction parameters (β σ , β M ) from surface tension-concentration data by use of Rosen's equations based on the nonideal solution theory. All the systems investigated adapt reasonably well to the nonideal model, with negative values of β σ and β M (where M means micelle and σ refers to the air-liquid interface) indicating a favorable interaction between the mixed surfactants. Either at a monolayer or in a mixed micelle, the attractive interaction becomes stronger when the alkyl chain in the POE surfactant is longer, i.e., when the POE becomes more hydrophobic. The interaction increases in the order C 10 E 7 < C 10 E 5 < C 12 E 3 , C 12 E 2 . For the two C 10 E n (n = 5,7)/C 12 E 3 S systems, as temperature increases from 25 to 40°C, the interaction increases in a mixed micelle, but it decreases in a mixed monolayer. Synergism in mixed micelle formation exists for C 12 E 3 S/C 10 E n mixtures when X 1 M , the mole fraction of POE in a mixed micelle, is ~0.4-0.8, whereas synergism does not occur in the systems of C 12 E 3 S/C 12 E m due to the large difference between CMC 1 and CMC 2 , i.e., large ln(C 1 M /C 2 M ) value (where CMC = critical micelle concentration). The degree of synergism in mixed micelle formation is temperature independent and is 0.23, 0.18, and close to zero for C 10 E 5 /C 12 E 3 S, C 10 E 7 /C 12 E 3 S, and C 12 E m (m = 2,3)/C 12 E 3 S systems, respectively. Synergism in surface tension reduction effectiveness occurs in C 12 E 3 S/C 12 E 2 and C 12 E 3 S/C 12 E 3 systems. The mole fractions of POE in the solution phase are 0.302 and 0.333 for the two mixtures at the point of maximum synergism.

Structural Studies of Nonionic Dodecanol Ethoxylates at the Oil–Water Interface: Effect of Increasing Head Group Size

“…Much is known about bulk properties of dodecanol ethoxylates such as cloud point as a function of increasing n 6 or properties of mixed micelles containing C 12 E n . 7,8 The addition of C 12 E n to SDS solutions efficiently reduces the solubilization of zein proteins, thus reducing the extent to which the detergent formulations will provoke adverse skin reactions. 9 Interfacial behavior at the solid−water interface has been reported for a number of different substrates such as graphite, 10 silicon, 11 and cellulose.…”

Wetting Power in Aqueous Mixtures of Alkylpolyglucosides and Ethoxylated Fatty Alcohols

“…In most practical applications, mixtures of surfactants are used and the behavior of the mixture is often different from the single surfactant, and in some cases synergistic effects are observed [2,3]. Consequently, lower quantities of surfactants are needed in these cases to achieve the same effect [4][5][6][7][8].…”

Surface properties, micellar molecular interaction, and physical properties for binary systems of sodium oleate with three anionic surfactants

“…From Table 1, the values of f 1 is far greater than f 2 even at lower α NaOL which implies that the effective concentration of NaOL in mixed micelles is far greater than another surfactant. [27] . From NaOL/SDS at α NaOL =0.67, 0.83.…”