Silica ionogels synthesized with imidazolium based ionic liquids in presence of supercritical CO2

• The presence of imidazolium based ionic liquids shortens the gelation time of one-pot synthesized silica ionogels.
• Supercritical carbon dioxide acts as co-catalyst and reduces the gelation time of silica ionogels.
• The ionogels, containing the IL with the most hydrophobic anion [Tf2N] show the longest gelation times.
• The ionic liquids remain confined in to the gels structure after the supercritical extraction process.

Silica ionogels were synthesized using the one step sol–gel route. Imidazolium based ionic liquids (ILs) containing different cations and anions were used in order to investigate their effect as co-solvent and co-catalyst on the gelation time and on the solid properties (pore size, surface area, pore volume, hydrophobicity) of the final material. The influence of the ionic liquid concentration on the gelation time was also determined. Experiments under high pressure in presence of supercritical carbon dioxide were additionally performed. The obtained ionogels were dried with supercritical CO2 and analyzed by scanning electron microscopy (SEM), 1H and 19F magic–angle spinning nuclear magnetic resonance (MAS NMR) and nitrogen adsorption–desorption isotherms (BET).

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