Emulsions and Foams Stabilized by Pickering Crystals

Commonly used food, pharma and personal care products are emulsions or foams in which the fluid-fluid interfaces are stabilised by excipients that crystallise at the interface from the continuous phase. We prepare two-dimensional fluid-fluid interfaces stabilised by crystals of monostearate, a commonly used excipient, and quantify the strength and relaxation dynamics of the interfaces as a function of excipient loading by means of interfacial shear rheology. Further, we propose a model that would predict the force required to induce a certain degree of phase separation, with only the microstructure and the interfacial elasticity as the input parameters. The predictions of the proposed model were validated by artificially inducing phase separation by means of centrifugation for the prepared foams and emulsions.