Three commentaries on the nano-segregated structure of ionic liquids

Effect of immobilization of titanocene catalyst in aralkyl imidazolium chloroaluminate media on performance of biphasic ethylene polymerization and polyethylene properties

“…The latter, depending on the relative size of the high-and low-charge regions in each ion, can exist as isolated (dispersed) islands or a second continuous phase. [56]. The non-polar regions of the aralkyl ionic liquids consist of aromatic moieties maintained by ring-stacking interactions, whereas 2 Cl is used instead of AlEtCl 2 .…”

Novel 2-alkyl-1-ethylpyridinium ionic liquids: synthesis, dissociation energies and volatility

“…5 The interaction between these two types of regions (polar and nonpolar) led to the recognition of ionic liquids as high-charge density (polar) networks permeated by low-charge density (nonpolar) regions. [1][2][3][4][5][6] This characteristic of the structural organization of ionic liquids was first experimentally supported by X-ray diffraction 7 and later by small-wide angle X-ray scattering (SWAXS). 8,9 Neutron diffraction was used to study the structures of 1,3-dimethylimidazolium chloride, 10 [C 1 C 1 im] [Cl], and hexafluorophosphate, 11 [C 1 C 1 im][PF 6 ], ionic liquids.…”

“…7,15 Recently, a comprehensive molecular dynamics simulation study has been performed in order to complement and extend the structural analysis on the mesoscopic segregation observed in the ionic liquids of the 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [C NÀ1 C 1 im][NTf 2 ]. 16 It was found that in the smaller members (C2-C4) of the ionic liquid series, the nonpolar aggregates form elongated clusters with an increasing number of tails per aggregate, which become more oblate around [C 5 16 The possibility of concisely tuning the physical-chemical properties by changing the cation-anion combination is one of the biggest advantages of these systems. For this purpose, the knowledge and understanding of structure-property relationships of ionic liquids is indispensable.…”

“…56 In these studies, the effect of the alkyl chain length of the cation was explored in order to get more insights about the nanostructuration of ionic liquids, which is related to the transition from a dispersed to a continuous non-polar phase, as the alkyl-side chain of the cation becomes longer. 5 It was possible to give a thermodynamic view of the nanostructuration of the imidazolium bistriflamide ionic liquids, for which a limit for the beginning of the nanostructuration/nano segregation at C 6 was observed. 50,55,57 Recently, the first volatility study of the 1-alkylpyridinium bis 50,51 It was found that the volatility of pyridinium ionic liquids is five times lower than that of imidazolium and that it is driven by their higher enthalpy of vaporization.…”

Evidence of nanostructuration from the heat capacities of the 1,3-dialkylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquid series

“…16,17 Recently, the studies exploring mesoscopic structural heterogeneities in ionic liquids has been compiled and discussed in order to give a better understanding on the nature of structural heterogeneities in ILs. 18 Shimizu et al, 19 based on molecular dynamics simulation, have shown that the structural segregation in ILs depends on the size of the polar and nonpolar regions. These regions can exist as isolated (dispersed) islands or a second continuous phase, in which the transition from a dispersed to a continuous non-polar phase corresponds to the nanostructuration limit.…”