EMULSIFICATION IN VISCOELASTIC MEDIA

We have created stable monodisperse emulsions by shearing and rupturin g crude polydisperse emulsions of larger droplets into smaller droplet s having a unique size. To eliminate inhomogeneous fracture flow which can lead to nonuniform rupturing and broad polydispersity, we use a s hearing geometry with a narrow gap. We can control the final droplet s ize by altering the shearing conditions and the emulsion's viscoelasti city which depends on its composition. We argue that the high degree o f monodispersity, indicated by Bragg scattering from colloidal crystal s of droplets, may result from a capillary instability that includes t he role of the emulsion's viscoelasticity.