Enhancement of the particle stabilization of water-in-water emulsions by modulating the phase preference of the particles.

HYPOTHESIS

The stability of particle stabilized water-in-water (W/W) emulsions depends on the position of the particles at the interface, which in turn depends on their preference for each phase. The surface properties of the particles determine their preference and it should therefore be possible to enhance the stability of W/W emulsions by modulating the surface of particles, for instance by adsorption of small molecules on their surface.

EXPERIMENTS

Polystyrene latex particles were covered with proteins to varying extents by adding different amounts of whey proteins. The effect on the efficacy of the particles to stabilize W/W emulsions formed by mixing dextran and poly(ethylene oxide) (PEO) was studied using confocal laser scanning microscopy and visual observations. Both emulsions with droplets of the PEO rich phase in a continuous dextran rich phase (P/D) and the inverse (D/P) were investigated.

FINDINGS

The preference of the particles could be modulated from strongly preferring the PEO phase in the absence of protein to preferring dextran phase in excess protein. It was found that the particles stabilized emulsions best when they preferred the continuous phase, i.e. protruded outward from the droplets. Both D/P emulsions and P/D could be stabilized at intermediate coverage.