Effects of 1‐Alkyl‐(and 1‐Benzyl)‐2,3‐Dimethylimidazolium Ionic Liquids as Additives on the Micellar Behavior of Surfactant SB‐12

Abstract

The micellization and surface-active behavior of zwitterionic surfactant N-dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (SB-12) in aqueous media were investigated in the absence and presence of different alkyl-appended and benzyl-appended ionic liquids (IL)The characteristics of self-organization processes in SB-12 + IL/water systems include critical micelle concentration (cmc), aggregation number (N agg ), micellar size (D), surface, and adsorption parameters. These parameters were determined by the fluorescence and surface tension measurements. In SB-12 solutions, cmc were found to be decreasing to different extents in the presence of all the studied IL than in pure water. The addition of IL [hdmim][Br] decreases the cmc of aqueous SB-12 to rather a low extent. The other three IL show a prominent lowering in cmc of surfactant SB-12 to different magnitude. The maximum lowering in cmc was observed due to addition of benzyl-appended IL [bzdmim] [Cl]. The aggregation number of aqueous SB-12 solution obtained in general is higher at high wt.% of added IL. The average micellar size was also found to increase upon addition of IL. Both IL anions and cations interacted with the charged centers present on the zwitterionic surfactant SB-12, which caused a substantial increase in the surface activity.Keywords Critical micelle concentration Á Benzyl appended ionic liquid Á SB-12 Á Tensiometry Á Fluoremetry J Surfact Deterg (2019) 22: 327-338. Synthesis of 1-Benzyl-2,3-Dimethylimidazolium Chloride [bzdmim][Cl]IL [bzdmim][Cl] was synthesized by slowly adding slight excess of benzyl chloride (10 g, 79 mmol) to 1,2dimethylimidazole (7.2 g, 75 mmol) in a round bottom flask. The resulting solution was refluxed between 60 and 70 C for 24 h under a N 2 atmosphere. After this, the reaction mixture was allowed to cool down and the product obtained was washed three times using diethyl ether. The solid product obtained dried under vacuum gives 1-benzyl-2,3dimethylimidazolium chloride [bzdmim] [Cl]. The reaction yields 85% of product. The water content determined through Karl-Fisher examination was found to be <380 ppm. 328 J Surfact Deterg J Surfact Deterg (2019) 22: 327-338

Scrutinizing Self-Assembly, Surface Activity and Aggregation Behavior of Mixtures of Imidazolium Based Ionic Liquids and Surfactants: A Comprehensive Review

“…Another category of surfactant namely zwitterionic surfactants is very little studied in the presence of ILs. However, Pal and Pillania ( 2019 ) determines the effect of addition of 1-butyl-2,3-dimethylimidazolium chloride [bdmim][Cl], 1-butyl-2,3-dimethylimidazolium bromide [bdmim][Br], 1-hexyl-2,3-dimethylimidazolium bromide [hdmim][Br], and 1-benzyl-2,3-dimethylimidazolium chloride [bzdmim][Cl] on the micellization and surface-active behavior of zwitterionic surfactant N-dodecyl-N,N-dimethyl- 3-ammonio-1-propanesulfonate (SB-12). The lowering in value of CMC of SB-12 has been observed with the addition of different concentrations of ILs.…”