[emim][etSO₄] as the Polar Phase in Low-Temperature-Stable Microemulsions

Abstract

We demonstrate here that microemulsions with an IL as the continuous phase can be formed so that they are stable over a wide temperature range and have intermediary properties between flexible and stiff microemulsions. Three components (1-ethyl-3-methylimidazolium ethylsulfate ([emim][etSO(4)]), limonene, and octylphenol ethoxylate (Triton X 100, abbreviated as TX-100)) were used. This ternary system has been characterized from ambient temperature down to -10 °C by means of conductivity, viscosity, and small-angle X-ray scattering (SAXS) measurements. The SAXS data exhibit a characteristic single, broad scattering peak in conjunction with a typical q(-4) decay at large q values. The SAXS data have also been interpreted in terms of a dimensionless dilution plot, demonstrating that microstructures are neither isolated droplets nor a random flexible film structure but resemble molten liquid crystals (i.e., they are formed from locally cylindrical or planar structures). This semirigidity is attributed to a good match between the surfactant and the ionic liquid; this holds in a temperature range well below 0 °C.

Influence of chemical architecture of oils and ionic liquid on the physicochemical and thermodynamic properties and microenvironment of anionic surfactant based microemulsion

“…However, use of LIM and IBB as oil in these formulations is not arbitrary. Reports on formation and properties of microemulsions in LIM and IBB oils are not much reported in literature [25][26][27][28][29][30]. LIM, the main constituent of peel oil from oranges and other citrus fruits, is an inexpensive monoterpenic hydrocarbon produced from a renewable source and widely available in the market.…”

Influence of surfactant amphiphilicity on the phase behavior of IL-based microemulsions

“…The ternary phase diagram was recorded at 25 ± 0.2°C according to the same procedure reported before [23]. ''Fish''-cuts were determined by weighing 1:1 mass ratio [emim][etSO 4 ] and limonene (a = 0.5 with a ¼ m o =ðm o þ m w Þ where m o and m w represents the mass of the oil and the water phase, respectively) and adding the appropriate amount of surfactant under inert atmosphere.…”

“…In a former publication, we reported characteristics of microemulsions composed of [emim][etSO 4 ]/limonene/Triton X-100 (TX-100) with the purpose to develop low-temperature-stable microemulsions [23]. A high potential of these systems exists for several applications, e.g.…”

Phase Manifestation and Formation of Nanoemulsions Composed of Imidazolium-based Ionic Liquid, Tween 80/Span 80 and Labrafac Lipophile WL 1349

“…The first ILbased microemulsion was reported by Gao et al (2004) where an IL was used to replace water content (Zech et al 2010). In the subsequent investigations, various kinds of IL-based microemulsions have been prepared (Zech et al 2010;Harrar et al 2011;Behera, Dahiya & Pandey 2007;Zhang et al 2011;Cheng et al 2007). In most of the studies on ILbased microemulsions, the IL, such as 1-butyl-3-methylimidazolium tetrafluoroborate (C 4 mim) (BF 4 ), was used as a replacement for water .…”