The higher the charge density of PILs the higher their Tg and the lower their conductivity; the best conductivity (1.8 × 10−5 S cm−1 at 25 °C): PILs with triazolium cations; the best cathodic stability (−0.4 V vs. Li+/Li at 70 °C): PILs with mixed type cations.

The proliferation of high-performance thin-film electronics depends on the development of highly conductive solid-state polymeric materials. We report on the synthesis and properties investigation of well-defined cationic and anionic poly(ionic liquid) AB−C type block copolymers, where the AB block was formed by random copolymerization of highly conductive anionic or cationic monomers with poly(ethylene glycol) methyl ether methacrylate, while the C block was obtained by postpolymerization of 2-phenylethyl methacrylate. The resulting ionic block copolymers were found to self-assemble into a lamellar morphology, exhibiting high ionic conductivity (up to 3.6 × 10 −6 S cm −1 at 25 °C) and sufficient electrochemical stability (up to 3.4 V vs Ag + /Ag at 25 °C) as well as enhanced viscoelastic (mechanical) performance (storage modulus up to 3.8 × 10 5 Pa). The polymers were then tested as separators in two all-solid-state electrochemical devices: parallel plate metal−insulator−metal (MIM) capacitors and thin-film transistors (TFTs). The laboratoryscale truly solid-state MIM capacitors showed the start of electrical double-layer (EDL) formation at ∼10 3 Hz and high areal capacitance (up to 17.2 μF cm −2 ). For solid-state TFTs, low hysteresis was observed at 10 Hz due to the completion of EDL formation and the devices were found to have low threshold voltages of −0.3 and 1.1 V for p-type and n-type operations, respectively.

This work aims to explore the gas permeation performance of two newly-designed ionic liquids, [C2mim][CF3BF3] and [C2mim][CF3SO2C(CN)2], in supported ionic liquid membranes (SILM) configuration, as another effort to provide an overall insight on the gas permeation performance of functionalized-ionic liquids with the [C2mim]+ cation. [C2mim][CF3BF3] and [C2mim][CF3SO2C(CN)2] single gas separation performance towards CO2, N2, and CH4 at T = 293 K and T = 308 K were measured using the time-lag method. Assessing the CO2 permeation results, [C2mim][CF3BF3] showed an undermined value of 710 Barrer at 293.15 K and 1 bar of feed pressure when compared to [C2mim][BF4], whereas for the [C2mim][CF3SO2C(CN)2] IL an unexpected CO2 permeability of 1095 Barrer was attained at the same experimental conditions, overcoming the results for the remaining ILs used for comparison. The prepared membranes exhibited diverse permselectivities, varying from 16.9 to 22.2 for CO2/CH4 and 37.0 to 44.4 for CO2/N2 gas pairs. The thermophysical properties of the [C2mim][CF3BF3] and [C2mim][CF3SO2C(CN)2] ILs were also determined in the range of T = 293.15 K up to T = 353.15 K at atmospheric pressure and compared with those for other ILs with the same cation and anion’s with similar chemical moieties.