A Pickering emulsion is stabilized by particles adsorbed at the liquid–liquid interface. A partially wetting sphere removes a patch of that interface. The smaller detachment barrier into either bulk phase is approximatelywhere is the three-phase contact angle. At approximately neutral wetting, , the stated particle radius givesat . Such a large attachment energy makes thermal detachment unlikely. A sufficiently covered interface resists drop coalescence, and a water-wet particle preference supports an oil-in-water dispersion. However, radius alone does not guarantee stabilization: completely water-wet or oil-wet particles have a vanishing attachment barrier in this model, and sufficient particle coverage is necessary. Sedimentation and droplet ripening are separate failure modes. The classical particle-stabilized-emulsion experiments provide the historical basis of the terminology.[ref]
CXCVI.—Emulsions by Spencer Umfreville Pickering. Journal of the Chemical Society, Transactions 91 (1907), pp. 2001–2021