Anomalous and Not-So-Common Behavior in Common Ionic Liquids and Ionic Liquid-Containing Systems

Esperança, José M. S. S.; Tariq, Mohammad; Pereiro, Ana B.; Araújo, João M. M.; Seddon, Kenneth R.; Rebelo, Luís Paulo N.

doi:10.3389/fchem.2019.00450

Cited by 30 publications

(23 citation statements)

References 99 publications

(139 reference statements)

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“…The literature also describes a “2/3 golden rule”, which means that for all compounds, that ratio of the temperatures of glass transition and melting (T g /T m ) is around 0.66 [ 20 ]. Lately, it was shown that for aprotic ionic liquids, the usual value of the ratio is 0.75 [ 17 ].…”

Section: Resultsmentioning

confidence: 99%

Influence of Alkyl Chain Length on Thermal Properties, Structure, and Self-Diffusion Coefficients of Alkyltriethylammonium-Based Ionic Liquids

Markiewicz

Klimaszyk

Jarek

et al. 2021

IJMS

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The application of ionic liquids (ILs) has grown enormously, from their use as simple solvents, catalysts, media in separation science, or electrolytes to that as task-specific, tunable molecular machines with appropriate properties. A thorough understanding of these properties and structure–property relationships is needed to fully exploit their potential, open new directions in IL-based research and, finally, properly implement the appropriate applications. In this work, we investigated the structure–properties relationships of a series of alkyltriethylammonium bis(trifluoromethanesulfonyl)imide [TEA-R][TFSI] ionic liquids in relation to their thermal behavior, structure organization, and self-diffusion coefficients in the bulk state using DSC, FT-IR, SAXS, and NMR diffusometry techniques. The phase transition temperatures were determined, indicating alkyl chain dependency. Fourier-transformed infrared spectroscopy studies revealed the structuration of the ionic liquids along with alkyl chain elongation. SAXS experiments clearly demonstrated the existence of polar/non-polar domains. The alkyl chain length influenced the expansion of the non-polar domains, leading to the expansion between cation heads in polar regions of the structured IL. 1H NMR self-diffusion coefficients indicated that alkyl chain elongation generally caused the lowering of the self-diffusion coefficients. Moreover, we show that the diffusion of anions and cations of ILs is similar, even though they vary in their size.

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Section: Resultsmentioning

confidence: 99%

Influence of Alkyl Chain Length on Thermal Properties, Structure, and Self-Diffusion Coefficients of Alkyltriethylammonium-Based Ionic Liquids

Markiewicz

Klimaszyk

Jarek

et al. 2021

IJMS

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“…Indeed, conditioning of the sample at −10 • C for 10 min, after it has previously been cooled to −100 • C, yields a clear, sharp melting peak in the third heating curve, proving that for nucleation to start, the IL needs to reach a sufficiently low temperature for nucleation to occur and then needs to be kept for a longer time just below the melting temperature. The observed supercooling of the pure IL during the normal heat-cool cycles is generally an indication of its high purity [35], but the complete suppression of crystallization in the polymer is an indication of good molecular-level dispersion.…”

Section: Thermal Propertiesmentioning

confidence: 99%

Tailoring the Thermal and Mechanical Properties of PolyActiveTM Poly(Ether-Ester) Multiblock Copolymers Via Blending with CO2-Phylic Ionic Liquid

et al. 2020

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The last decade has seen an exponential increase in the number of studies focused on novel applications for ionic liquids (ILs). Blends of polymers with ILs have been proposed for use in fuel cells, batteries, gas separation membranes, packaging, etc., each requiring a set of specific physico-chemical properties. In this work, blends of four grades of the poly(ether-ester) multiblock copolymer PolyActive™ with different concentrations of the CO2-philic 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [BMIM][Tf2N] were prepared in the form of dense films by a solution casting and solvent evaporation method, in view of their potential use as gas separation membranes for CO2 capture. Depending on the polymer structure, the material properties could be tailored over a wide range by means of the IL content. All samples were dry-feeling, highly elastic self-standing dense films. The microstructure of the blends was studied by scanning electron microscopy with a backscattering detector, able to observe anisotropy in the sample, while a special topographic analysis mode allowed the visualization of surface roughness. Samples with the longest poly(ethylene oxide terephthalate) (PEOT) blocks were significantly more anisotropic than those with shorter blocks, and this heterogeneity increased with increasing IL content. DSC analysis revealed a significant decrease in the melting enthalpy and melting temperature of the crystalline PEOT domains with increasing IL content, forming an amorphous phase with Tg ≈ −50 °C, whereas the polybutylene terephthalate (PBT) phase was hardly affected. This indicates better compatibility of the IL with the polyether phase than the polyester phase. Young’s modulus was highest and most IL-dependent for the sample with the highest PEOT content and PEOT block length, due to its high crystallinity. Similarly, the sample with short PEOT blocks and high PBT content also showed a high modulus and tensile strength, but much lower maximum elongation. This study provides a detailed discussion on the correlation between the morphological, thermal, and mechanical properties of these PolyActive™/[BMIM][Tf2N] blends.

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“…Ionic liquids (ILs) are a diverse and fascinating class of materials. As salts with comparably low melting pointsoften even below room temperature (RT)they combine typically very low vapor pressures with a large number of tunable chemical and physicochemical properties, depending on the numerous possible pairings of cations and anions [1][2][3][4][5][6][7][8][9][10][11][12][13]. One of the most successful applications involving bulk amounts of ILs is the BASIL TM process for the production of alkoxyphenylphosphines [14,15].…”

Section: Introductionmentioning

confidence: 99%

Ultrathin ionic liquid films on metal surfaces: adsorption, growth, stability and exchange phenomena

Lexow

Maier

Steinrück

2020

Advances in Physics: X

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The interface of ionic liquids (ILs) with solid surfaces is of pivotal interest for many applications, ranging from sensors, lubrication, separation technology, and electronics to electrochemistry and catalysis. We present a short review on ultrathin layers of ionic liquids on metal surfaces using a surface science approach. We mainly focus on specific examples of imidazolium-based ionic liquids on Ag(111) and Au(111) studied by angle-resolved X-ray photoelectron spectroscopy, and relate the obtained results to existing literature. We address a variety of phenomena on the molecular level, namely, (i) the adsorption, growth and wetting behavior of ILs, (ii) the thermal stability and desorption of ILs, (iii) exchange processes of anions and cations at the IL/solid interface, and (iv) the replacement of ILs from the IL/solid interface by porphyrins.

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Anomalous and Not-So-Common Behavior in Common Ionic Liquids and Ionic Liquid-Containing Systems

Cited by 30 publications

References 99 publications

Influence of Alkyl Chain Length on Thermal Properties, Structure, and Self-Diffusion Coefficients of Alkyltriethylammonium-Based Ionic Liquids

Influence of Alkyl Chain Length on Thermal Properties, Structure, and Self-Diffusion Coefficients of Alkyltriethylammonium-Based Ionic Liquids

Tailoring the Thermal and Mechanical Properties of PolyActiveTM Poly(Ether-Ester) Multiblock Copolymers Via Blending with CO2-Phylic Ionic Liquid

Ultrathin ionic liquid films on metal surfaces: adsorption, growth, stability and exchange phenomena

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