Ionic liquids in microemulsions

Qiu, Zhiming; Texter, John

doi:10.1016/j.cocis.2007.10.005

Cited by 199 publications

(127 citation statements)

References 38 publications

(29 reference statements)

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“…Indeed, monolayer enrichment of alkyl chains in imidazolium based ILs has been observed in angle-resolved x-ray photoelectron studies of the vapour/liquid interface (Lockett et al , 2008b;Maier et al , 2010), indicating the important role of attractive forces at the interface. Related to this are the observations of small-angle X-ray scattering experiments that appear to indicate structure on the mesoscale due to the incompatibility of the ionic and non-polar parts of cationic molecules, with sufficiently long carbon chains (Qiu & Texter , 2008). It has been conjectured that these structures are responsible for the unique solvent properties of some ILs, and to their ability to impart stability to dispersions of metallic nanoparticles.…”

Section: Coarse-grained Models and Dielectric Responsementioning

confidence: 99%

A Classical Density Functional Theory of Ionic Liquids

2011

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Classical Density Functional Theory of Ionic Liquids 3 Other approachesILs are fascinating from a theoretical standpoint. In order to treat ILs, a theory must account for both electrostatic and steric correlations. Attempts to develop such a theory have appeared in the literature. These include the lattice based model by Kornyshev and co-workers (Fedorov et al. , 2008;Kornyshev , 2007). In another lattice approach by Lauw and coworkers (Lauw et al. , 2009), both cations and anions were modelled by a star-like architecture, with each monomer subject to an independently specified dielectric response. Under certain circumstances, these models were able to qualitatively reproduce the so-called "camel-shaped" differential capacitance, C D , profile observed in imidazolium ILs at carbon electrodes (Islam et al. , 2009;Lockett et al. , 2008a). This behaviour is an indication of subtle structuring effects at charged surfaces and is a stern test for theory. Although camel-shaped C D profiles are predicted, qualitative discrepancy against experimental results remains. This is not surprising since these crude theories lack a proper description of electrostatic correlations despite accounting for steric contributions. Charge-charge correlations have been shown to be important in interfacial phenomena of highly coupled electrostatic fluids. As with dispersion forces, ionic correlations are always attractive and lower the total energy. Thus, we expect that they will also play a role in establishing the camel shape of the C D . That this is the case, is seen from both simulations (Lamperski & Zydor , 2007;Vatamanu et al. , 2010) (Fedorov et al. , 2010;Trulsson et al. , 2010), play an important role in determining their properties. In this work, we will use a model for ILs wherein the molecular ions interact via dispersion, as well as electrostatic, forces and the cation has an oligomeric structure consistent with imidazolium ions. This model has also been adopted by us in previous recent publications (Forsman et al. , 2011;Trulsson et al. , 2010), and employs the methods of polymer free energy density functional theory (DFT) (Woodward , 1991). The result will be a simple, albeit approximate DFT for ILs. We have already introduced the salient features of the theory in a previous publication (Forsman et al. , 2011). Here, we will present a much more thorough treatment, emphasizing the relation to theories of simpler fluids. We will also extend the scope of the study with some emphasis on temperature dependence and the effects of ion-specific adsorption. The IL-DFT that we will discuss here is an off-lattice theory, whose accuracy can be straightforwardly tested against computer simulations of the same molecular model. We will begin with a discussion of relevant earlier work, in order to introduce the essential mechanistic components that will be combined in our density functional theory for ionic liquids. Classical density functional theory (DFT) of simple fluidsThe ideal gas law is known and used by most physicists and chemist...

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Section: Coarse-grained Models and Dielectric Responsementioning

confidence: 99%

A Classical Density Functional Theory of Ionic Liquids

2011

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“…15,[20][21][22] Several reviews on the actual state of the art of ILs and microemulsions have also been published. [23][24][25][26] Gao et al were the first to discover that [bmim] [BF 4 ] assembles in polar nanosized droplets when dispersed in cyclohexane as solvent. 11 Recently, Han and his co-workers discovered that the 1,1,3,3-tetramethylguanidinium type of ILs can be dissolved in supercritical CO 2 reverse micelles.…”

Section: Introductionmentioning

confidence: 99%

The effect of water on the microstructure and properties of benzene/[bmim][AOT]/[bmim][BF4] microemulsions

Bai¹,

Ge²,

Gao³

et al. 2013

Phys. Chem. Chem. Phys.

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“…Nonetheless, the droplet sizes inferred from DLS measurements of the order of 0.1 µm at R = 1.5 appear to be extraordinary large and are outside the range of conventional microemulsions. These outstandingly large droplet dimensions may be related to collective scattering effects that have not been taken into account (Qiu & Texter 2008). Eastoe et al performed small angle neutron scattering (SANS) experiments on the same systems at 55°C, except that cyclohexane-d 12 was used to improve the scattering contrast (Eastoe et al, 2005).…”

Section: Aprotic Ionic Liquidsmentioning

confidence: 99%

“…Apart from these applications, ILs also stimulated research in classical colloid and surface chemistry. The formation of amphiphilic association structures in and with ionic liquids, such as micelles, vesicles, microemulsions and liquid crystalline phases has been reviewed three times between 2007 (Hao & Zemb 2007) and 2008 (Qiu & Texter 2008;, reflecting the growing interest and progress in this field. In this review we focus on ILs in nonaqueous microemulsions, because significant new work has been reported in this field since these earlier reviews have been published.…”

Section: Introductionmentioning

confidence: 99%