STATIC MULTIPLE LIGHT SCATTERING TO PREDICT LONTERM STABILITY OF EMULSIONS WITH POLYMERS

INTRODUCTION AND LITERATURE MICROSCOPIC APPROACH Polymers are widely used in the industry to control viscosity, provide end use properties and enhance the shelf life. At high concentration, the polymer stabilizes the emulsion forming a percolated network, which can persist for a very long period of time (months), but ended always to collapse and giving two separated phases. This kind of emulsions is very problematic for industry as no method exists to predict the breaking of the emulsions, samples can be qualified stables in QC-tests and break after during commercialization. Teece & al. show from confocal microscopy measurements that for O/W emulsions with xanthan, droplets form a network with strands of thickness ls and mesh size  depending on polymer concentration (see figure hereunder). They correlate this size properties with visual observation of destabilization. The smaller the cages and the thinner the strands, the longest the delayed collapse. This method with confocal microscopy detection is powerful but not ready to use for industry, requires to add fluorescent agent, to have experience to fix parameters and obtain good quality images.