Competition between hydrogen bonding and electrostatic repulsion in pH-switchable emulsions

•Electrostatic repulsion can overcome hydrogen bonding in oil-in-water (O/W) emulsions stabilized by the mixture of a biosurfactant escin and hydrophilic silica nanoparticles triggered by pH.•Reversible conversion between Pickering and OID emulsions can be achieved by the structural transformation of escin at different pH.•Pickering or OID emulsions with high internal phase volume fraction can be obtained.