Oil-in-oil Pickering emulsions stabilized by shigaite-like layered double hydroxide particles

In this work, we report the preparation of simple oil-in-oil emulsions using layered nanoparticles as stabilizers at the interface between silicone and castor oil. Layered double hydroxides with a shigaite-like structure presenting an ideal composition of [Mn6Al3(OH)18][(SO4)2Na].12H2O (S-Na/SO4) were prepared by co-precipitation with increasing pH, followed by particle surface grafting with octhadecyltrimethoxysilane (S-OTMS) in an apolar medium. The powder XRD, SEM, TEM, and specific surface area (BET) techniques showed that the structure and morphology of silane-grafted S-Na/SO4 remained practically unchanged. FTIR, EDS and ICP-OES analyses indicated that the silanes were successfully grafted onto the S-Na/SO4 surface. In addition, to maintaining their structure and morphology, these functionalized materials showed good performance in controlling the hydro-phobicity of the surface for application in oil-in-oil emulsions, improving their compatibility for the dispersion in non-polar liquids.