Pickering emulsions stabilized by naturally derived or biodegradable particles

Emulsions are used widely in formulated consumer products, paints and coatings, foods, and pharmaceutical preparations to name just a few examples. Frequently surfactants are employed as emulsifiers, but the use of particles, including nanoparticles, can offer advantages. Naturally derived, or synthetic, particles that are biodegradable can reduce end-of-life environmental impact, while offering advantages such as lack of irritancy in use ( e.g ., on skin) and, in some cases, the use of particle supported Pickering emulsions may provide more environmentally friendly processes ( e.g ., biphasic catalysis mitigating use of solvents) or environmental cleanup solutions ( e.g ., oil spill dispersion). Here we review four classes of (nano)particles that can be employed as Pickering emulsion stabilizers: minerals, polysaccharides, synthetic polymers and proteins.