A Study of the Interactions in a Ternary Surfactant System in Micelles and Adsorbed Layers

Abstract

Surface tension and neutron reflection measurements have been used to study the micellization and interfacial adsorption of ternary surfactant mixtures containing sodium dodecyl sulfate (SDS), n-dodecyl-N,Ndimethylaminoacetate (C 12 Betaine or C 12 B), and n-dodecyl-β-D-maltoside (C 12 M). Critical micelle concentrations (cmc) for the ternary mixtures are compared with values predicted using a multicomponent extension to the pseudophase separation model for nonideal mixing. Although the observed cmcs may be up to 50% different from those predicted, the errors resulting from inadequacies in the binary model mean that the results are the same within error. Values of the surface excesses at the air/solution interface at the cmc were determined directly using neutron reflection and isotopic substitution. They are found to be quite different from those predicted using the binary interaction parameters determined by surface tension. However, if the apparent binary interaction parameters obtained from directly measured compositions in the binary systems are used, the agreement between prediction and experiment is much improved. This suggests that prediction of the properties of ternary surfactant mixtures may be relatively straightforward once mixing in binary mixtures is properly characterized.

Formation of model lipid bilayers at the silica-water interface by co-adsorption with non-ionic dodecyl maltoside surfactant

“…The surfactant used to solubilize the lecithin was n-dodecylb-D-maltoside (purity b98%, molecular weight 510X6 g/mol) purchased from Sigma Chemicals. The cmc of the surfactant is reported to be 1X67 Â 10 À4 mol/L (Hines et al 1998) ( 8X53 Â 10 À5 g/L). In this paper, we refer to these substances as lecithin and DDM, respectively.…”

Comparison of the Coadsorption of Benzyl Alcohol and Phenyl Ethanol with the Cationic Surfactant, Hexadecyl Trimethyl Ammonium Bromide, at the Air–Water Interface

“…This has now been extensively demonstrated on a range of different mixed surfactant systems (5)(6)(7)(8)(9)(10)(11), in surfactant/alcohol mixtures (12) and surfactant/alkane mixtures (13).…”

“…Following the procedure adopted for the C 16 TAB/benzyl alcohol mixture, measurements were made with the labelled combinations, dC 10 hC 6 hTAB/d-pe/nrw, dC 10 hC 6 hTAB/h-pe/nrw, hC 16 hTAB/h-pe/D 2 O, hC 16 hTAB/d-pe/nrw, and hC 16 hTAB/ d-pe/D 2 O. From the combination dC 10 hC 6 hTAB/d-pe/nrw we have [11] and from the combination hC 16 …”

“…[11] and [12] the cross-terms h c1pe and h pes can be obtained. A similar expression for h c2pe can be derived using the combination hC 10 dC 6 hTAB/d-pe/nrw.…”

Markov chain model for the critical micelle concentration of surfactant mixtures

“…Ternary surfactant mixtures receive significant attention in the literature, especially in the last decade [10,[33][34][35][36]. We will therefore investigate also the problem for micellization in a ternary surfactant mixture from the viewpoint of Markov chain mechanism.…”