Switchable pickering emulsions stabilized by silica nanoparticles hydrophobized in situ with a switchable surfactant.

Back and forth: The CO2 /N2 trigger of a switchable surfactant (neutral amidine/cationic amidinium) was transferred to mineral nanoparticles through in situ hydrophobization in water. Switchable oil-in-water Pickering emulsions that entail a CO2 /N2 trigger were obtained by using negatively charged silica nanoparticles and a trace amount of the switchable surfactant as the stabilizer.