Oil powders and gels from particle-stabilized emulsions.
We report on the use of silica particle-stabilized oil-in-water emulsions as a template for the preparation of oil powders and gels obtained in a single step by either slow or rapid evaporation of water using freeze-drying or spray-drying, respectively. Using olive oil and partially hydrophobic fumed silica nanoparticles, an oil powder containing nearly 90 wt % oil can be formed by spray-drying, which shows no sign of oil leakage over several months. Upon slow evaporation of water by freeze-drying, a transparent oil gel with oil content as high as 98 wt % can be formed, in which the silica particles form a space-filling network thickening the oil. Comparisons are made throughout with a typical surfactant-stabilized emulsion which does not produce oil powders or gels.
Surfactant & Colloid Group, Department of Chemistry, University of Hull, Hull HU6 7RX, United Kingdom.
Horst
H
Adelmann
Bernard P
BP
Binks
Raffaele
R
Mezzenga
D004655:Emulsions / Q000737:chemistry*; D005612:Freeze Drying; D057927:Hydrophobic and Hydrophilic Interactions; D053758:Nanoparticles / Q000737:chemistry*; D000069463:Olive Oil; D010938:Plant Oils / Q000737:chemistry*; D011208:Powders / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D013501:Surface-Active Agents / Q000737:chemistry
D004655:Emulsions; D000069463:Olive Oil; D010938:Plant Oils; D011208:Powders; D013501:Surface-Active Agents; D012822:Silicon Dioxide