Well-defined ABA-triblock copolymers, polystyreneblock-poly(methyl methacrylate)-block-polystyrene (SMS), which have two different polystyrene (PSt) weight fractions (f PSt ), were synthesized by successive atom-transfer radical polymerizations. Ion gels consisting of SMS and an ionic liquid, (1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide [C 2 mim][NTf 2 ]), were prepared using the cosolvent evaporation method with tetrahydrofuran. Atomic force microscope images of the ion gels indicated that PSt is phase-separated to form sphere domains that serve as physical cross-linking points because PSt is not compatible with [C 2 mim][NTf 2 ], while a continuous poly(methyl methacrylate) (PMMA) phase with dissolved [C 2 mim][NTf 2 ] is formed to serve as ion conduction paths. Accordingly, the ion gels are formed by the self-assembly of SMS and the preferential dissolution of [C 2 mim]-[NTf 2 ] into the PMMA phase. The viscoelastic properties of the gels can be easily controlled by changing f PSt in SMS and [C 2 mim][NTf 2 ] concentration in the ion gels. The ion gels that exhibit high ionic conductivities (>10 −3 S cm −1 ) at room temperature were used as an electrolyte of an ionic polymer actuator, which has a trilaminar structure consisting of the ion-gel electrolyte sandwiched between two composite carbon electrodes containing high-surface-area activated carbon powders. By applying low voltages (<3.0 V) to the electrodes, the actuator exhibited a soft bending motion toward the anodic side.

To understand the important factors that dominate colloidal stability in ionic liquids (ILs), rheology of the dispersions of hydrophilic and hydrophobic silica nanoparticles were investigated in ILs with different ionic structures. The dispersion of hydrophilic silica nanoparticles in [BF(4)] anion-based ILs and in an IL containing a hydroxyl group, 1-(2-hydroxyethyl)-3-methylimidazolium bis(trifluoromethane sulfonyl)amide ([C(2)OHmim][NTf(2)]), showed an intriguing shear thickening response. Nonflocculation of the hydrophilic silica nanoparticles in the [BF(4)] anion-based ILs and in [C(2)OHmim][NTf(2)], where the interparticle electrostatic repulsion appears to be depressed, suggests that an IL-based steric hindrance or solvation force provides an effective repulsive barrier for the colloidal aggregation. On the other hand, the other dispersions presented shear thinning behavior with an increase in shear rates and gelled at relatively low particle concentrations. The elastic modulus (G') of the gels formed by the hydrophilic silica was correlated with the polarity scale, lambda(Cu), of the ILs, indicating that the silica-IL interactions, especially the silica-anion interactions, appear to affect the rheological behavior, even in flocculated systems. All the ILs used in this study can be solidified by the addition of hydrophobic silica particles. The rheological behavior of the silica colloidal dispersions was strongly affected by the ionic structure of the ILs and the surface structure of the silica particles.

† Electronic supplementary information (ESI) available: Synthesis, method and supplementary data for fitting parameters obtained from the VTF equation for ionic conductivity (Table S1), photographs of the ion gel (Fig. S1) and TGA (Fig. S2).

We report a new class of polymer electrolytes that exhibit high Li + -ionic conductivity and thermal stability up to 200 °C. The polymer electrolyte consists of a solvate ionic liquid ([Li(G4)][TFSA]), comprising an equimolar mixture of lithium bis(trifluoromethanesulfonyl)amide (Li[TFSA]) and tetraglyme (G4), and a well-defined ABA-triblock copolymer, polystyrene-b-poly(methyl methacrylate)-b-polystyrene (PStb-PMMA-b-PSt, SMS). The electrolyte is formed by the selfassembly of SMS, where the solvatophobic PSt segments serves as physical cross-linking points, and the solvatophilic PMMA segment with preferentially dissolved [Li(G4)][TFSA] forms ion-conduction paths. In the electrolyte, the preservation of the complex cation [Li(G4)] + in the PMMA phase was demonstrated by pulsed-field gradient spin−echo (PGSE) NMR, Raman spectra, and thermogravimetric analysis. Because of the preservation of [Li(G4)] + , which hinders the direct interaction of Li + with the polymer segment and the coupling of the ionic transport from the segmental motion, the room temperature ionic conductivity of the electrolyte reached an appreciable level (10 −4 −10 −3 S cm −1 ).

Keywords: solvate ionic liquid polymer electrolyte polymer-in-salt ionicity glyme A B S T R A C T Polymer electrolytes (PEs) have served as the focus of intensive research as new ion-conducting materials, especially for lithium battery applications. A new strategy to develop fast lithium-conducting PEs is reported here. The thermal, ionic transport, and electrochemical properties of polymer solutions in a glyme-Li salt solvate ionic liquid, [Li(G4) 1 ][TFSA], composed of an equimolar mixture of lithium bis (trifluoromethanesulfonyl) amide (Li[TFSA]) and tetraglyme (G4), were characterized. Poly(ethylene oxide) (PEO), poly(methyl methacrylate) (PMMA), and poly(butyl acrylate) (PBA) were combined with [Li(G4) 1 ][TFSA] in order to explore the effects of polymer structure on the properties. The self-diffusion coefficient ratio of the glyme and Li + ions (D G /D Li ) was investigated to evaluate the stability of the complex (solvate) cations. The D G /D Li values suggested that the [Li(G4) 1 ] + complex cations underwent a ligand exchange reaction between G4 and PEO in the PEO-based solution, whereas the cations remained stable (D G /D Li = 1) in the PMMA-and PBA-based solutions. The robustness of the [Li(G4) 1 ] + complex cations in the PMMA-and PBA-based solutions was reflected in high weight-loss temperature, greater Li transference number, and high oxidative stability.Owing to the lower glass transition temperature and low affinity towards Li + ions, the PBA-based solutions yielded superior lithium transport properties (ionic conductivity of 10 À4 $10 À3 Scm À1 and Li transference number as high as 0.5) among the investigated polymer solutions.