Synergistic Effect of Binary Surfactant Mixtures in Two-Phase and Three-Phase Systems

Abstract

Cationic alkyltrimethylammonium bromides (C n TAB, with n = 8, 12, 16, 18) and their mixtures with n -octanol as a nonionic surfactant were chosen as a model system to study the synergistic effect on foamability (two-phase system) and floatability (three-phase system) of quartz in the presence of binary mixtures of ionic/nonionic surfactants. The foam height of one-component solutions and binary mixtures and floatability of quartz particles were characterized as a function of the surfactant concentration and the number of carbons ( n ) in the alkyl chain of C n TAB. The experimental results of foamability and floatability measurements in one-component and mixed solutions revealed the synergistic effect, causing a significant enhancement in the foam height and recovery of quartz. In the presence of n -octanol, the height of foam increased remarkably for all C n TAB solutions studied, and this effect, whose magnitude depended on the C n TAB hydrophobic tail length, could not be justified by a simple increase in total surfactant concentration. A similar picture was obtained in the case of flotation response. The mechanism of synergistic effect observed in mixed C n TAB/ n -octanol solutions was proposed. The discussion was supported by molecular dynamics simulations, and the probable mechanism responsible for synergism was discussed. In addition, an analysis allowing accurate determination of the concentration regimes, where the synergistic effect can be expected, was given. It was shown that for the two-phase system, the n -octanol molecule preadsorption at the liquid/gas interface causes an increase in C n TAB adsorption coverage over the level expected from its equilibrium value in the one-component solution. In the case of the three-phase system, the synergistic effect was related to the ionic surfactants serving as an anchor layer for n -octanol, which, in water/ n -octanol solution (one-component system), do not adsorb on the surface of quartz.

Influence of Surfactant Concentration on Spontaneous Emulsification Kinetics

“…This is consistent with the fact that CTAB adsorption results in a better neutralization of the water/PO interface charge, with respect to SDS adsorption, that is also reflected by a different stability of the corresponding emulsions. These results are also consistent with previous studies that reported about the synergistic interactions between non-ionic and cationic surfactants. − For instance, the adsorption of CTAB was enhanced due to the synergies between CTAB and TX-100 (Triton X-100, a non-ionic surfactant) . A similar behavior was also reported for the surfactant mixture of DDAB (didodecyldimethylammonium bromide, a cationic surfactant) and Igepal CO-890 (polyoxyethylene-40 nonylphenyl ether, a non-ionic surfactant) in oil-in-water emulsions .…”

Self-Assembly and Micellar Transition in CTAB Solutions Triggered by 1-Octanol

“…28 Wiertel-Pochopien et al proposed the mechanism of synergistic effect in mixed C n TAB−C 8 OH solutions in two-phase and threephase systems, and the discussion was supported by MD simulations. 29 However, MD simulation with rheology and small-angle neutron scattering (SANS) studies have scarcely concentrated on the quantitative effect of C 8 OH on CTAB micelles. Thus, our study aims to scrutinize the influence of long-chain alcohol, viz., C 8 OH, on tuning the micellar morphology of CTAB, giving an account of the phase behavior, rheology, and SANS measurements.…”

“…In addition to the experimental approach, theoretical studies have also offered a better understanding of surfactant solutions expressed in terms of interfacial properties and structural transitions in the presence of alcohols at the atomistic level over the last decade. ,− However, the molecular dynamics (MD) simulation approach in this direction is still not explored widely. ,− The MD carried out on cationic surfactant in the presence of alcohols is thought to be the most straightforward method. ,− Verma et al performed the atomistic-level study of cetylpyridinium bromide (CPB) surfactant by MD simulations, which was then verified by investigating its structural and dynamic properties in water, C 8 OH, and micelle . Jia et al examined the shape and structural evolution of preassembled cylindrical CTAB micelles in the presence of C 8 OH by MD simulations .…”

“…Jia et al examined the shape and structural evolution of preassembled cylindrical CTAB micelles in the presence of C 8 OH by MD simulations . Wiertel-Pochopien et al proposed the mechanism of synergistic effect in mixed C n TAB–C 8 OH solutions in two-phase and three-phase systems, and the discussion was supported by MD simulations …”

Virtual Issue on Surfactants

“…Finally, it was concluded that some micelle demixing is occurring between the gemini and the zwittergent under certain micellar composition ranges, a phenomenon rarely associated with hydrocarbon surfactants. Again, Tan et al synthesized novel "linear" trisiloxane surfactants with different terminal groups (CH 3 −, ClCH 2 −, CF 3 −) and two polyether hydrophilic groups followed by successful characterization using the 1 H NMR, 13 C NMR, 29 Si NMR, and FTIR spectroscopy. 8 In addition to this, the aggregation and adsorption behaviors of these surfactants in aqueous solution were studied by surface tension, dynamic light scattering (DLS), and transmission electron microscopy (TEM).…”