ELASTICITY OF COMPRESSED EMULSIONS

The elastic shear modulus of monodisperse emulsions is shown to exhibit a universal dependence on droplet volume fraction phi when scaled by the Laplace pressure of the droplets, increasing as phi(phi - phi(c)). where phi(c) approximate to 0.635, the value of random close packing of solid spheres. Surprisingly the osmotic pressure required to compress the emulsions to increase phi is nearly the same as the shear modulus over a large range of volume fraction, while the bulk osmotic modulus differs significantly. Models based on the structural disorder of the emulsions are discussed to account for these data.