Ionic Liquid-Based Surfactants: Recent Advances in Their Syntheses, Solution Properties, and Applications

Abstract

The impetus for the expanding interest in ionic liquids (ILs) is their favorable properties and important applications. Ionic liquid-based surfactants (ILBSs) carry long-chain hydrophobic tails. Two or more molecules of ILBSs can be joined by covalent bonds leading, e.g., to gemini compounds (GILBSs). This review article focuses on aspects of the chemistry and applications of ILBSs and GILBSs, especially in the last ten years. Data on their adsorption at the interface and micelle formation are relevant for the applications of these surfactants. Therefore, we collected data for 152 ILBSs and 11 biamphiphilic compounds. The head ions of ILBSs are usually heterocyclic (imidazolium, pyridinium, pyrrolidinium, etc.). Most of these head-ions are also present in the reported 53 GILBSs. Where possible, we correlate the adsorption/micellar properties of the surfactants with their molecular structures, in particular, the number of carbon atoms present in the hydrocarbon “tail”. The use of ILBSs as templates for the fabrication of mesoporous nanoparticles enables better control of particle porosity and size, hence increasing their usefulness. ILs and ILBSs form thermodynamically stable water/oil and oil/water microemulsions. These were employed as templates for (radical) polymerization reactions, where the monomer is the “oil” component. The formed polymer nanoparticles can be further stabilized against aggregation by using a functionalized ILBS that is co-polymerized with the monomers. In addition to updating the literature on the subject, we hope that this review highlights the versatility and hence the potential applications of these classes of surfactants in several fields, including synthesis, catalysis, polymers, decontamination, and drug delivery.

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

“…Other applications of SAILs can be listed as foaming and antifoaming agents, antimicrobials, demulsification of crude oil, chromatographic and electrophoretic separations, enhanced oil recovery (EOR), solubilization of drugs, extraction of natural products etc. (Shah et al, 2018a , 2020 ; Vaid et al, 2018a , b ; Dani et al, 2019 ; Isosaari et al, 2019 ; Kuddushi et al, 2019 , 2020 ; Shakeel et al, 2019 ; Lee et al, 2020 ; Nandwani et al, 2020 ; El Seoud et al, 2021 ). SAILs can be of different kinds based upon their structure.…”

Adsorption Properties of Hydrocarbon and Fluorocarbon Surfactants Ternary Mixture at the Water-Air Interface

“…The ability of surfactants to adsorb at various interfaces and to form micelles in the bulk phase determines their wetting, emulsifying, solubilizing, dispersing, and foaming properties [1]. These properties are the basis for the wide application of surfactants in various industrial fields: pharmacy, medicine, agriculture, and in everyday life [2][3][4][5]. The practical application of surfactants depends on their structure, namely the type and size of the hydrophobic and hydrophilic groups in the surfactant molecules and the types of groups that give these properties [1][2][3][4][5].…”

“…These properties are the basis for the wide application of surfactants in various industrial fields: pharmacy, medicine, agriculture, and in everyday life [2][3][4][5]. The practical application of surfactants depends on their structure, namely the type and size of the hydrophobic and hydrophilic groups in the surfactant molecules and the types of groups that give these properties [1][2][3][4][5]. Surfactant molecules undergo hydration in the aqueous environment.…”

“…Unfortunately, it is difficult Molecules 2021, 26, 4313 2 of 21 to find a surfactant that would exhibit all the good properties. Therefore, in practice, mixtures of various surfactant types are used [2][3][4][5]. The application of a surfactant mixture is often associated with the occurrence of a synergistic effect in the reduction of water surface tension.…”

“…For these studies Triton X-100 (TX100), cetyltrimethylammonium bromide (CTAB), Zonyl FSN-100 (FC6EO14, FC1) and Zonyl FSO-100 (FC5EO10, FC2) were chosen. These surfactants are very interesting from the practical point of view and can be treated as model surfactants in different mixtures [ 2 , 3 , 4 , 5 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ]. Thus, the aim of the paper was attained by the measurements of the surface tension ( ) of the ternary surfactant mixtures as a function of fluorocarbon surfactant concentration at the constant concentration of CTAB and TX100 mixture corresponding to their aqueous solution surface tension equal to 60 and 50 mN/m [ 17 ] and the saturated monolayer at the water−air interface.…”