STABILITY OF EMULSIONS WITH NONADSORBING POLYMERS

We present an experimental study of the effects of hydrophilic, nonads orbing polymers on the stability of monodisperse oil-in-water emulsion s. Above some threshold polymer concentration, the chains induce dropl et segregation into fluid and solid phases due to the depletion effect . At higher polymer concentrations, polymers induce the formation of g el-like structures of droplets. Phase diagrams of droplet volume fract ion versus polymer concentration are presented. At large droplet volum e fractions where droplets are deformed, the polymers enhance consider ably the stability of the emulsion against droplet coalescence. We com pare our results with recent experiments and models of colloid-polymer mixtures.