Supramolecular Ionic Liquid Gels with Tunable Conductivity Based on Host-Guest Interaction

Regulating the conductivity of ionic liquid gels in a wide range to meet different demands in various fields has attracted the increasing attention of researchers. Herein, we report on the preparation of an ionic liquid gel with tunable conductivity via a supramolecular strategy. A class of linear pillar[5]arene-containing polymers with different backbones were synthesized by combining metathesis cyclopolymerization and ring-opening metathesis polymerization. Upon addition of an ionic guest, the glass transition temperatures of such polymers decreased dramatically, which led to the increase of conductivity. Owing to the host-guest complexation between the pendant pillararenes of polymers and pyridinium groups of guest molecules, as well as the interaction between Li⁺ and the ethyl oxide group, supramolecular ionic liquid gels were formed, of which the conductivity could be tuned in the range of 7.91 × 10^-6-3.03 × 10^-3 S·cm^-1 by diverse methods, including adjusting the temperature, structures of pillararene-containing polymers and guest molecules, and molar ratios of guest/host and LiTFSI/guest.