Structural effects of polyethers and ionic liquids in their binary mixtures on lower critical solution temperature liquid-liquid phase separation

Abstract

The solubility and phase behavior of five polyethers (poly(ethylene oxide), poly(glycidyl methyl ether), poly(ethyl glycidyl ether), poly(ethoxyethyl glycidyl ether) and poly(propylene oxide)) in 14 different room-temperature ionic liquids (ILs) were studied by changing the structures of polyethers and the cations and anions in the ILs. Certain combinations of a polyether and an IL binary mixture exhibited lower critical solution temperature (LCST) phase behavior. For ILs containing the same anions, the polyethers were highly soluble in imidazolium-or pyridinium-based ILs, whereas they were insoluble in ammonium-or phosphonium-based ILs. An increase in length of the alkyl chain in the imidazolium cation and an increase in polarity of the polyethers resulted in a higher LCST phase separation temperature, whereas substitution of the hydrogen atoms on the imidazolium ring by methyl groups resulted in a lower LCST phase separation temperature. The hydrogen bonding interaction between the oxygen atoms in the polyethers and the aromatic hydrogen atoms on the cations in the ILs had an important role in the LCST phase behavior of the mixtures. Miscibility of the mixtures was also affected by the Lewis basicity of the anions in the ILs.

Ionic liquid-nanoparticle hybrid electrolytes

“…20 C1C3imTFSI has also been investigated as a catalyst for the hydroformylation of alkenes, 21 as an attractive medium for electrodeposition of tantalum, 22 and as a solvent for extraction of aromatic compounds from aliphatic hydrocarbons. 23 Dlubek et al studied C1C3imTFSI using PALS (position annihilation lifetime spectroscopy) and reported a glass transition at a temperature T g ¼ 187 K, a melting transition at a temperature T c ¼ 200 K, and a significant increase in the hole free volume fraction, which determines the temperature-dependence of viscosity, from 0.023 at 185 K to 0.17 at 430 K. 24 Xiao et al have shown that the asymmetry of the C1C3imTFSI cation plays an important role in setting the low-frequency vibrational dynamics of the IL and in determining its relatively low melting point. 25 Pure C1C3imTFSI has been reported with an ionic conductivity of 7.42 Â 10 À3 S cm À1 at 30 C. 26 When doped with the salt LiTFSI in a 1 : 1 molar ratio, the material is reported to exhibit a markedly lower ionic conductivity (e.g.…”

Temperature and light-induced self-assembly changes of a tetra-arm diblock copolymer in an ionic liquid

“…11,12 For example, poly(N-isopropylacrylamide) (PNIPAm) shows an upper critical solution temperature (UCST) phase transition in certain ILs, which is a completely opposite phenomenon to that observed in aqueous solutions. 13 In contrast, certain polymethacrylates [14][15][16] or polyether derivatives [17][18][19] are found to exhibit lower critical solution temperature (LCST) phase behavior in ILs. Phase transitions of polymers in nonvolatile and thermally stable ILs can afford long-term stable smart materials without solvent evaporation.…”

Adsorption of Polyether Block Copolymers at Silica–Water and Silica–Ethylammonium Nitrate Interfaces

“…Three polyethers with various fractions of PEO were synthesized as previously reported, 53 with the molecular weights (M n ) and polydispersity indexes (PDI) presented in Table 1 Sample Preparation. Polymer/water and polymer/EAN samples with various polymer concentrations (0.1 and 1 wt %) were stirred overnight in a sealed glass vial at room temperature prior to measurements.…”