Low-Molecular-Weight Supramolecular Ionogel Based on Host–Guest Interaction

Supramolecular ionogels were prepared by self-assembly of small molecules through host–guest interaction between β-cyclodextrin (β-CD) and a room-temperature ionic liquid (IL) 3-(1-methyl-3-imidazolio)propanesulfonate-lithium bis(trifluoromethanesulfonyl)imide (MIPS-LiTFSI) which contains zwitterion MIPS. 19F NMR and 2D ROESY 1H NMR have been used to prove that only TFSI– is involved in the complexation. 1H NMR, FT-IR, and comparative tests indicated that the electrostatic interaction between imidazole cation and TFSI– anion and intermolecular hydrogen bonding between three compounds also contribute to the formation of supramolecular ionogel. Ionogels with different gel–sol phase transition temperatures can be obtained by adjusting the molar ratio between β-CD and MIPS-LiTFSI. In addition, the supramolecular ionogels composed of “channel type” structural β-CD have been constructed. The ionogel with high conductivity and low activation energy open a door to new fields for special applications.