Surface and Solution Properties of Alkanediyl-α,ω-bis(dimethylcetylammonium bromide) Gemini Surfactants in the Presence of Additives

Abstract

Herein, we report the results of a study of surface and micellar properties of alkanediyl-α,ω-bis(dimethylcetylammonium bromide) gemini surfactants in pure aqueous solutions and also in the presence of alcohols (butanol, hexanol) and amines (butylamine, hexylamine). Parameters studied include cmc (critical micelle concentration), C 20 (concentration required to reduce the surface tension of the solvent by 20 mN·m−1), Γm a x (maximum surface excess concentration at the air/solution interface), and A min (minimum area per surfactant molecule). These parameters indicate mixed micellization between the surfactants and alcohols/amines; therefore, surfactant−additive interactions in mixed micelles and mixed monolayers, as well as activity coefficients, are also calculated. All the results show that high additive concentrations destabilize micelles: ΔG ex (excess free energy of micellization) becomes more negative at low additive concentrations (i.e., micelles stabilize) and less negative at high concentrations (i.e., micelles destabilize).

Mixed micelles of amphiphilic drug promethazine hydrochloride and surfactants (conventional and gemini) at 293.15 K to 308.15 K: Composition, interaction and stability of the aggregates

“…Cmc as well as aggregate properties of the aggregates are governed by several factors like nature and size of counterions, structure of amphiphile molecules and their concentrations. The cmc values of the pure components agree well with the literature values [27][28][29][30]. As is clear from Scheme 1, drug molecule's hydrophobic portion is short and rigid and, therefore, forms aggregates at higher concentrations as compared to surfactants.…”

Effect of spacer length on the micellization and interfacial behavior of mixed alkanediyl-α,ω-bis(dimethylcetylammonium bromide) Gemini homologues

“…In line with the earlier reports [37,52], the cmc of 16-6-16 is found more than that of the other two Geminis. The cmc's of the pure surfactants agree well with the literature values [23,[53][54][55].…”

“…Further increase in spacer length in 16-6-16 surfactant increases the flexibility of spacer paving way for the head groups to come closer again resulting in the increase in charge density and hence counterion binding. Such turn over in the properties of Gemini surfactants above spacer length of 5 has been observed earlier as well [53,62]. In case of binary systems (Fig.…”

Micellization and micellar growth of alkanediyl-α,ω-bis(dimethyldodecylammonium bromide) surfactants in the presence of medium-chain linear alcohols

“…Since in their applications, surfactants are frequently used in the presence of alcohols, the study of how the addition of alcohols affects the aggregation and micellar growth of 12-s-12,2Br À solutions is of interest. Micellization of 12-2-12,2Br À surfactants, with s = 2, 6, and 16-s-16,2Br À surfactants, with s = 4, 5, 6, in the presence of various alcohols have recently been carried out [7,8]. However, to our knowledge, no investigations about the influence of medium-chain linear alcohols on the second critical micelle concentration, C Ã , of 12-s-12,2Br À surfactants have been done.…”