Development of water-in-oil Pickering emulsions from sodium oleate surface-modified nano-hydroxyapatite

The stabilisation of water-in-oil (W/O) Pickering emulsions is still a challenge for the scientific community. In this work, sodium oleate (SO) surface modified nano-hydroxyapatite (n-HAp) particles were produced and tested as W/O stabilisers. n-HAp presented wettability dependent on used SO content, switching from hydrophilic (initial state) to hydrophobic (one layer) back (two layers). with holding one layer (contact angle ∼90 °) showed their tight adsorption at water-oil interface (confocal analysis), maintained stability up 15 days. Overall work provides new developments in field emulsions, topic less studied than O/W, opening avenues several applications.