Binary and Ternary Phase Behaviors of Short Double-Chain Quaternary Ammonium Amphiphiles: Surface Tension, Polarized Optical Microscopy, and SAXS Investigations

Abstract

A series of short chain dialkyldimethylammonium amphiphiles ([DiC(n)][X] and [DiC(n)]2[X] with n = 6, 8, or 10) has been investigated as a function of the nature of the counteranion [X] (Cl(-) and Br(-) as classical references and MoO4(2-) and WO4(2-) as catalytic anions). Critical aggregation concentrations (CACs) in water were determined by surface tension measurements, and the binary phase diagrams of the surfactant/water systems were established using polarized optical microscopy (POM) and small angle X-ray scattering (SAXS). The evolution of microstructures and lyotropic phases were discussed in terms of surfactant chain length and counterion effect. A cubic phase region was observed for the divalent counteranions associated with the intermediate chain length, i.e., [DiC8]2[MoO4] and [DiC8]2[WO4]. Finally, the fish diagrams reflecting the polyphasic microemulsion phase behavior of the water/amphiphile/oil ternary systems were established using the carbon number of mono- and dichlorinated n-alkanes as a scan variable. The amphiphile efficiency was also discussed according to the chain length and the nature of the counterions. The hydrophilic-lipophilic behavior of the amphiphiles was evaluated on the basis of the fish diagrams allowing their classification according to the Hofmeister anion sequence. The unusual behavior of [DiC8][Cl] and [DiC8]2[MO4] (M = W or Mo) is highlighted by all experiments: these compounds are clearly intermediates between hydrotropes, [DiC6] cation, and surfactants, [DiC10] cation.

Physicochemical Properties and Phase Behavior of Didecyldimethylammonium Chloride/Alkyl Polyglycoside Surfactant Mixtures

“…Previous work has indicated that double-tailed cationic surfactants have been widely used as fabric softeners, antimicrobials, and antistatic agents [20] in many formulations because of their strong absorbability onto negative surfaces. APG and didecyldimethylammonium chloride (DDAC) mixtures, combining the advantages of pure APG and DDAC, are of particular interest and importance in the development of multi-functional disinfection and washing products [21][22][23][24].…”

Cation Effect on the Binary and Ternary Phase Behaviors of Double‐Tailed Methanesulfonate Amphiphiles

“…All the solutions were prepared with Ultrapure water (Millipore water, σ = 72.0 mNÁm −1 at 25 C). The surface tension was measured as reported in previous works (Hong et al, 2013). was prepared.…”

Lyotropic liquid crystal phase behavior of a cationic amphiphile in aqueous and non-stoichiometric protic ionic liquid mixtures

“…16,21 While numerous amphiphile/IL/co-solvents have been investigated, the vast majority are microemulsions where the IL has been used as the amphiphile, the polar phase or as the nonpolar phase. [39][40][41][42] We previously used a high-throughput approach to characterize a broad range of aqueous, non-stoichiometric PIL solvents in terms of surface tension, apparent pH and liquid nanostructure, which are the properties strongly affecting the ability of a solvent to promote self-assembly. 43 Our findings showed that the selected solvent properties can be tailored through varying the water content as well as the nonstoichiometry, and general trends for each solvent property were obtained.…”