Dielectric analysis of the [Bmim][PF6]/TX-100/ethyleneglycol nonaqueous microemulsions: Microstructures and percolation

Chen, Kai; Zhao, Kongshuang

doi:10.1016/j.colsurfa.2014.07.022

Cited by 21 publications

(14 citation statements)

References 53 publications

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“…Aer that, the dielectric measurements of ILs microemulsions which constructed by IL and TX-100 with water or oil were also respectively performed as mentioned above. 32,35,40 In these measurements, researchers observed another relaxation of higher radio frequency 10 7 to 10 8 Hz. Nevertheless, just as what have been used to interprete the relaxation of the IL/TX-100/water system, many possible relaxation mechanisms may contribute to this relaxation.…”

Section: Relaxation Mechanismmentioning

confidence: 92%

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Dielectric relaxation of nonaqueous ionic liquid microemulsions: polarization, microstructure, and phase transition

Zhang

Zhen

et al. 2017

RSC Adv.

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Two nonaqueous ionic liquid (IL) microemulsions (toluene/TX-100/[bmim] [PF 6 ] and [bmim] [BF 4 ]/TX-100/ benzene) were studied by dielectric spectroscopy covering a wide frequency range (40 Hz to 110 MHz).A unique relaxation was observed in the radio frequency (RF) range. By methodically analyzing the dependence of relaxation parameters on the ILs content, the microstructures of the microemulsions were identified. Additionally, based on the interfacial polarization theory and Einstein equation, the mechanism of the relaxation caused by the fluctuation of IL anions along the TX-100 PEO chain was confirmed, what's more, according to the dependence of the dc conductivity of the microemulsions on IL concentration, it was concluded that the hydrophilicity of the IL in the nonaqueous IL microemulsions may play a crucial role in the electrical conduction mechanism: our analysis results suggest that a dynamic percolation process occurs in the toluene/TX-100/[bmim][PF 6 ] system in which IL is hydrophobic, while a static percolation happens in benzene/TX-100/[bmim] [BF 4 ] where IL is hydrophilic.The otherness of relaxation time provides evidence that there is a possible coupling effect between IL and TX-100. Moreover, there are hints that all of the disparities, such as relaxation time, percolation type, ion migration rate and the size of different micro zones, may just stem from the different hydrophobicity of the two kinds of IL. Fig. 5 The diagram of dependency between relaxation time s and the mass fraction C IL (wt) of benzene/TX-100/[bmim][BF 4 ] (a) and toluene/TX-100/[bmim][PF 6 ] (b) ternary system where the concentration range have been divided into three areas.This journal is

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Section: Relaxation Mechanismmentioning

confidence: 92%

“…33 We recently reported the dielectric behavior of nonaqueous IL microemulsions and explained the percolation phenomena of systems combining percolation theory. 34,35 And these works rstly systematically discussed the solubility and polarity of ILs, the interaction between IL and TX-100, and percolation phenomena in the B.C. phase.…”

Section: Introductionmentioning

confidence: 99%

Dielectric relaxation of nonaqueous ionic liquid microemulsions: polarization, microstructure, and phase transition

Zhang

Zhen

et al. 2017

RSC Adv.

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“…As an alternative to traditional non-polar solvents to formulate microemulsion and/or RMs, ILs (hydrophobic) have been used as the external component [ 121 , 122 , 123 , 124 , 125 , 126 , 127 , 128 , 129 , 130 , 131 , 132 , 133 , 134 , 135 , 136 , 137 , 138 , 139 , 140 , 141 , 142 , 143 , 144 , 145 , 146 ]. Particularly, the most used hydrophobic IL is 1-butyl-3-methylimidazolium hexafluorophosphate (bmim-PF 6 ) [ 125 , 126 , 127 , 128 , 129 , 130 , 131 , 132 , 134 , 135 , 136 , 137 , 138 , 141 , 142 , 143 , 146 ]. Different surfactants have been employed such as Triton X-100 [ 125 , 126 , 127 , 128 , 129 , 130 ,…”

Section: Biocompatible Solvents As the External Phase In Rms And Microemulsions/nanoemulsionsmentioning

confidence: 99%

“…Particularly, the most used hydrophobic IL is 1-butyl-3-methylimidazolium hexafluorophosphate (bmim-PF 6 ) [ 125 , 126 , 127 , 128 , 129 , 130 , 131 , 132 , 134 , 135 , 136 , 137 , 138 , 141 , 142 , 143 , 146 ]. Different surfactants have been employed such as Triton X-100 [ 125 , 126 , 127 , 128 , 129 , 130 , 131 , 132 , 134 , 135 , 136 , 137 , 140 , 141 , 142 , 143 ], Tween 20 [ 138 ], and Na-AOT [ 123 , 124 , 139 , 143 , 146 ]. Moreover, water was almost exclusively the polar solvent dispersed.…”

Section: Biocompatible Solvents As the External Phase In Rms And Microemulsions/nanoemulsionsmentioning

confidence: 99%

Biocompatible Solvents and Ionic Liquid-Based Surfactants as Sustainable Components to Formulate Environmentally Friendly Organized Systems

et al. 2021

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In this review, we deal with the formation and application of biocompatible water-in-oil microemulsions commonly known as reverse micelles (RMs). These RMs are extremely important to facilitate the dissolution of hydrophilic and hydrophobic compounds for biocompatibility in applications in drug delivery, food science, and nanomedicine. The combination of two wisely chosen types of compounds such as biocompatible non-polar solvents and ionic liquids (ILs) with amphiphilic character (surface-active ionic liquids, SAILs) can be used to generate organized systems that perfectly align with the Green Chemistry concepts. Thus, we describe the current state of SAILs (protic and aprotic) to prepare RMs using non-polar but safe solvents such as esters derived from fatty acids, among others. Moreover, the use of the biocompatible solvents as the external phase in RMs and microemulsions/nanoemulsions with the other commonly used biocompatible surfactants is detailed showing the diversity of preparations and important applications. As shown by multiple examples, the properties of the RMs can be modified by changes in the type of surfactant and/or external solvents but a key fact to note is that all these modifications generate novel systems with dissimilar properties. These interesting properties cannot be anticipated or extrapolated, and deep analysis is always required. Finally, the works presented provide valuable information about the use of biocompatible RMs, making them a green and promising alternative toward efficient and sustainable chemistry.

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“…However, percolation in nonionic surfactant RMs have been sparsely studied. 9,10 We have extensively studied the shape, size, and internal structure of nonionic surfactant RMs in surfactant/ oil system for the last ten years. We have successfully underlined the fundamental understanding of the microstructure and morphology control of nonionic surfactant RMs.…”

mentioning

confidence: 99%

Percolation Behavior of Nonionic Reverse Micellar Solution

Aramaki¹,

Ichikawa²,

Shrestha³

2017

Chem. Lett.

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We report the percolation behavior of nonionic surfactant reverse micelles (RMs) composed of sorbitan laurate (Span20) and poly(oxyethylene) sorbitan monooleate (Tween80) in isopropyl myristate (IPM) in presence of a trace amount of water and electrolyte (KCl). Abrupt increase of conductivity above 20°C for oil/surfactant = 8/2 and Span20/Tween80 = 3/2 composition is an indication of the typical percolation behavior. The dynamic percolation behavior was suggested based on the scaling analysis of the conductivity change around the percolation temperature. Contrary to the ionic surfactant RMs, conductivity maxima was observed in the present nonionic RM system. Small-angle X-ray scattering (SAXS) data showed sphere-to-rod-type RM microstructure transition with increasing temperature in the lower temperature region. On the other hand, RM shrunk in the high temperature region due to dehydration of poly(oxyethylene) chains. It is anticipated that this characteristic feature of nonionic surfactant led to the depercolation at high temperatures.Keywords: Reverse micelle | Percolation | Conductivity Self-assembly has been recognized as a ubiquitous aspect of modern chemistry. 13 Reverse micelle (RM) or w/o microemulsion formed in nonpolar solvents, which is one of the surfactant self-assembled structures, has not been as extensively studied as the normal micelles in aqueous systems, in spite of several promising applications such as reaction media for nanomaterial preparation, chemical and biological reactions. Among the RM studies, electrical percolation behavior in ionicsurfactant-based systems has been extensively studied.46 Although RMs in nonaqueous systems show limited conductivity at low temperature or at low water concentration, the conductivity abruptly increases after a threshold temperature or water content. It is generally believed that such electrical percolation occurs because of clustering or transient fusion of RMs,7,8 which allows transfer of ions in the water pool of RMs. Percolation behavior in ionic surfactant (especially Aerosol OT) RM systems has been broadly investigated over the decades. However, percolation in nonionic surfactant RMs have been sparsely studied. 9,10 We have extensively studied the shape, size, and internal structure of nonionic surfactant RMs in surfactant/ oil system for the last ten years. We have successfully underlined the fundamental understanding of the microstructure and morphology control of nonionic surfactant RMs. 1113 Based on a decade-long experience on RMs, we aimed to study electrical percolation behavior of nonionic surfactant RM systems.Nonionic surfactants used in the present study, poly(oxyethylene) sorbitan monooleate (Tween80) and sorbitan laurate (Span20), were purchased from Sigma-Aldrich Co., and Tokyo Chemical Industry (TCI) Co., respectively. We chose those surfactants because it has been reported that nonionic reverse micelles or microemulsions can be formed using those surfactants.14,15 Isopropyl myristate (IPM) and potassium chloride (KCl) were purchas...

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Dielectric analysis of the [Bmim][PF6]/TX-100/ethyleneglycol nonaqueous microemulsions: Microstructures and percolation

Cited by 21 publications

References 53 publications

Dielectric relaxation of nonaqueous ionic liquid microemulsions: polarization, microstructure, and phase transition

Dielectric relaxation of nonaqueous ionic liquid microemulsions: polarization, microstructure, and phase transition

Biocompatible Solvents and Ionic Liquid-Based Surfactants as Sustainable Components to Formulate Environmentally Friendly Organized Systems

Percolation Behavior of Nonionic Reverse Micellar Solution

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