Anion effect on the aggregation behavior of the long-chain spacers dicationic imidazolium-based ionic liquids

Frizzo, Clarissa P.; Bender, Caroline R.; Gindri, Izabelle M.; Salbego, Paulo R. S.; Villetti, Marcos A.; Martins, Marcos A. P.

doi:10.1007/s00396-015-3680-y

Cited by 32 publications

(38 citation statements)

References 47 publications

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“…The former is related to the solvation of the counterions, while the latter alters the volume fraction of the hydrophilic block. In this study, the hydration radius of the anion follows the order: Brˉ < Iˉ < SCNˉ < PF 6 ˉ . From this aspect, the relatively hydrophilic volume is expected to increase as Brˉ is replaced by Xˉ, thus requiring a greater curvature to facilitate packing into the nano‐assemblies.…”

Section: Discussionmentioning

confidence: 90%

“…From this aspect, the relatively hydrophilic volume is expected to increase as Brˉ is replaced by Xˉ, thus requiring a greater curvature to facilitate packing into the nano‐assemblies. However, on the other hand, the hydration of four anions follows the order: Brˉ > Iˉ > SCNˉ > PF 6 ˉ, which suggests the hydrophilicity of cationic blocks decreases after Brˉ is replaced by Xˉ. The above two aspects have the opposite influence on the nature of corona segments in terms of the hydrophilicity as well as the volume fraction of hydrophilic block.…”

Section: Discussionmentioning

confidence: 97%

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Interplay of Solvation and Size Effects Induced by the Counterions in Ionic Block Copolymers on the Basis of Hofmeister Series

Luo

Tang

Zhong

et al. 2019

Macro Chemistry & Physics

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Two ionic block copolymers with different lengths of hydrophilic segments, polystyrene‐b‐poly(quaternized 4‐vinylpyridine)/ethyl bromide, are prepared by sequential reactions. They are originally self‐assembled into so‐called “large compound micelles” in aqueous solution. After ion exchange of Iˉ, SCN,ˉ and PF6ˉ for Brˉ, morphological transitions are controlled by a competition of solvation and size effects of the newly introduced counterions. The solvation effect is dominated in a relatively short corona‐forming block. Thus, sphere‐to‐wormlike particles, sphere‐to‐vesicle, and sphere‐to‐precipitate transitions are observed. In contrast, due to a long corona‐forming block, size effects become more profound after adding SCNˉ, thereby no morphological transition occurs. A morphological transition is characterized after partial exchange of Iˉ for Brˉ for both diblocks. A sphere‐to‐wormlike particles transition is observed only after most Brˉ is replaced by Iˉ. This work extends the understanding of morphological regulation through simple ion exchange and encourages rational design of nano‐assemblies.

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Section: Discussionmentioning

confidence: 90%

Section: Discussionmentioning

confidence: 97%

Interplay of Solvation and Size Effects Induced by the Counterions in Ionic Block Copolymers on the Basis of Hofmeister Series

Luo

Tang

Zhong

et al. 2019

Macro Chemistry & Physics

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“…1,2 Depending of the cation and anion combination, ILs may exhibit different physicochemical properties when compared with conventional electrolytes media or organic solvents. [3][4][5] Properties such as high thermal stability, tunable electrochemical window, low flammability, broad liquid range, and ability to dissolve and stabilize a wide range of materials allow ILs to be used in engineered materials synthesis. Imidazolium-based ILs are among the most studied classes of ILs.…”

Section: Introductionmentioning

confidence: 99%

Thermal Stability and Kinetic of Decomposition of Mono- and Dicationic Imidazolium-Based Ionic Liquids

Bender

Kuhn

Farias

et al. 2019

J. Braz. Chem. Soc.

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Phase transitions, thermal stability, thermokinetics and activation parameters of degradation reaction of the dicationic ionic liquids (ILs), 1,n-bis(3-methylimidazolium-1-yl)alkane ([BisAlk(MIM) 2 ][2Br]) and monocationic ILs, 1-(3-methylimidazolium-1-yl)alkane ([Alk(MIM)] [Br]), where Alk = Dec, DoDec, TetDec, (decane, dodecane, tetradecane) were evaluated. The influence of an additional cationic head and the alkyl chain length in thermal parameters were also evaluated. The dicationic ILs are more stable than monocationic and thermal degradation of ILs mono-and dicationic did not show linear dependence on the alkyl chain length. Thermokinetic parameters indicated degradation in multiple steps. The monocationic ILs showed a more persistent crystalline phase than dicationic IL, which became totally amorphous after heating. The estimate temperature decomposition, activation energy and thermal transitions enable the determination of which types of ILs are applicable for specific purposes, such as lubricants or solvents at high temperatures, while maintaining ILs physical and chemical properties.

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“…25,26 previous work. 16 The CAC obtained for these ILs corroborates with the hydration ability of 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 anions, based on free energy (∆G°h yd , Table 1) [28]. The values decrease in the following order:…”

Section: Resultsmentioning

confidence: 97%

“…13,14 Our research group has been developing important works in the area of ILs. 12,[15][16][17] Recently, we showed that longer spacer groups favor the aggregation of dicationic imidazolium-based ILs in water, when the side alkyl chains are shorter (methyl). 15 Additionally, we showed that the aggregation properties of dicationic ILs are dependent on anion hydrophobicity.…”

Section: Introductionmentioning

confidence: 99%

Elucidating Anion Effect on Nanostructural Organization of Dicationic Imidazolium-Based Ionic Liquids

Frizzo¹,

Bender²,

Gindri

et al. 2016

J. Phys. Chem. C

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This work reports the influence of anion structure (Br -, NO 3 -, BF 4 -, and SCN -) in the aggregation process of ionic liquids (ILs), derived from 1,8-bis(3-methylimidazolium-1-yl)octane, in 4.75% ethanol-water solution (v/v). The aggregation behavior was investigated using small angle x-ray scattering (SAXS), nuclear magnetic resonance (NMR), dynamic light scattering (DLS), and transmission electron microscopy (TEM). Spin-lattice relaxation times (T1), obtained by NMR, indicated that the molecular mobility of the ILs changed when aggregates are formed. 1 H-NMR showed distinct chemical shifts as a function of the concentration of [BisOct(MIM) 2 ][2X] (in which X = Br, NO 3 , SCN, and BF 4 ) in solution. This change was associated with different chemical environments experienced by the hydrogen atoms when the aggregation process occurs.This behavior was characterized by the different types of interactions in the aggregates, in accordance with the anion of the IL structure. The SAXS measurements demonstrated that the distance between two molecules, which function as scattering centers, was dependent on the anion hydrophobicity. Less hydrophobic anions resulted in shorter distances between scattering centers due to their better solvating ability. Due to the lower solvating ability of hydrophobic anions, a larger distance between two scattering centers was observed. Furthermore, ILs with more hydrophobic anions (e.g., BF 4 -) resulted in closely-packed aggregates.

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Anion effect on the aggregation behavior of the long-chain spacers dicationic imidazolium-based ionic liquids

Cited by 32 publications

References 47 publications

Interplay of Solvation and Size Effects Induced by the Counterions in Ionic Block Copolymers on the Basis of Hofmeister Series

Interplay of Solvation and Size Effects Induced by the Counterions in Ionic Block Copolymers on the Basis of Hofmeister Series

Thermal Stability and Kinetic of Decomposition of Mono- and Dicationic Imidazolium-Based Ionic Liquids

Elucidating Anion Effect on Nanostructural Organization of Dicationic Imidazolium-Based Ionic Liquids

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