Micellization of Two Triquaternary Ammonium Surfactants in Aqueous Solution

Adsorption of cationic ‘gemini’ surfactants at the TiO2/solution interface

“…11 Elaboration of the data of the two isotherms on the basis of the Frumkin-Fowler-Guggenheim model equation 12,13 (in the case of the gemini, only up to the monolayer region) produces quite different values of the adsorption Gibbs energy, i.e. 16 kJ mol 1 for the monomer and 26 kJ mol 1 for the gemini. The higher affinity of the gemini for the solid appears also from the strikingly larger adsorbed amounts apparent in Fig.…”

“…The critical micelle concentrations of geminis are always much smaller than for the corresponding monomeric surfactants, and the presence of gemini aggregates has a strong bearing on the rheology of the solutions. 1 Furthermore, geminis aggregate into micelles whose shape and size are highly sensitive to the length of the hydrophobic spacer, and this makes these molecules ideal tools for fundamental studies of self-assembly. 2 The possibility of tuning the molecule geometry and modulating the hydrophilic/hydrophobic relative weights allows gemini surfactants to be considered as very promising in studies concerning amphiphilic molecules adsorption at the solid/liquid interface.…”

Mixed Micellization of Dimeric (Gemini) Surfactants and Conventional Surfactants

“…• C. The micelle aggregation numbers were determined by means of the time-resolved fluorescence quenching technique using the previously described single-photon counting apparatus (30,31). The measurements were performed at 25, 40, and 55…”

A fluorescence probe study of gemini surfactants in aqueous solution: a comparison between n-2-n and n-6-n series of the alkanediyl-a,w-bis (dimethylalkylammonium bromides)

“…It is well known that pyrene exhibits a certain affinity for quaternary ammonium head groups, therefore the decrease for the I 1 /I 3 ratios indicates that aggregation numbers increase and some water molecules are removed from the solvation shell of pyrene [32][33][34]. This behavior may be due to the increasing aggregation numbers (N ) with concentration and this has been observed for dimeric surfactants having short as well as longer spacer groups [32,33]. The most noticeable is the higher I 1 /I 3 ratios obtained for the n-6-n micelles compared to those reported by the probe in the presence of the n-2-n surfactants (Fig.…”