Gelation of Ionic Liquids Using a Cross-Linked Poly(Ethylene Glycol) Gel Matrix

Conductive ionic liquid−poly(ethylene glycol) (IL−PEG) gels have been prepared by gelation of the hydrophobic ionic liquid 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C6mim][NTf2]) by the cross-linking reaction of disuccinimidylpropyl PEG monomers with four-arm tetraamine PEG cross-linkers. This is the first time that a cross-linked PEG matrix, such as this, has been used to gel nonaqueous solvents. Initial studies screening other ionic liquids as solvents indicate that the gelation of the ionic liquid is both cation and anion dependent with smaller, coordinating cations disrupting or preventing gel formation.