title: A step toward the development of high-temperature stable ionic liquid-in-oil microemulsions containing double-chain anionic surface active ionic liquid.
abstract: Owing to their fascinating properties and wide range of potential applications, interest in nonaqueous microemulsions has escalated in the past decade. In the recent past, nonaqueous microemulsions containing ionic liquids (ILs) have been utilized in performing chemical reactions, preparation of nanomaterials, synthesis of nanostructured polymers, and drug delivery systems. The most promising fact about IL-in-oil microemulsions is their high thermal stability compared to that of aqueous microemulsions. Recently, surfactant-like properties of surface active ionic liquids (SAILs) have been used for preparation of microemulsions with high-temperature stability and temperature insensitivity. However, previously described methods present a limited possibility of developing IL-in-oil microemulsions with a wide range of thermal stability. With our previous work, we introduced a novel method of creating a huge number of IL-in-oil microemulsions (Rao, V. G.; Ghosh, S.; Ghatak, C.; Mandal, S.; Brahmachari, U.; Sarkar, N. J. Phys. Chem. B2012, 116, 2850-2855), composed of a SAIL as a surfactant, room-temperature ionic liquids as a polar phase, and benzene as a nonpolar phase. The use of benzene as a nonpolar solvent limits the application of the microemulsions to temperatures below 353 K. To overcome this limitation, we have synthesized N,N-dimethylethanolammonium 1,4-bis(2-ethylhexyl) sulfosuccinate (DAAOT), which was used as a surfactant. DAAOT in combination with isopropyl myristate (IPM, as an oil phase) and ILs (as a polar phase) produces a huge number of high-temperature stable IL-in-oil microemulsions. By far, this is the first report of a huge number of high-temperature stable IL-in-oil microemulsions. In particular, we demonstrate the wide range of thermal stability of [C6mim][TF2N]/DAAOT/IPM microemulsions by performing a phase behavior study, dynamic light scattering measurements, and (1)H NMR measurements and by using coumarin-480 (C-480) as a fluorescent probe molecule.
authors.affiliation: Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, WB, India.
authors.forename: Vishal Govind
authors.initials: VG
authors.lastname: Rao
authors.forename: Chiranjib
authors.initials: C
authors.lastname: Banerjee
authors.forename: Surajit
authors.initials: S
authors.lastname: Ghosh
authors.forename: Sarthak
authors.initials: S
authors.lastname: Mandal
authors.forename: Jagannath
authors.initials: J
authors.lastname: Kuchlyan
authors.forename: Nilmoni
authors.initials: N
authors.lastname: Sarkar
mesh_terms: D000838:Anions / Q000737:chemistry; D004655:Emulsions / Q000737:chemistry; D052578:Ionic Liquids / Q000737:chemistry*; D015394:Molecular Structure; D009226:Myristates / Q000737:chemistry*; D009821:Oils / Q000737:chemistry*; D013499:Surface Properties; D013696:Temperature
chemical_list: D000838:Anions; D004655:Emulsions; D052578:Ionic Liquids; D009226:Myristates; D009821:Oils; C008205:isopropyl myristate