Abstract
We present an experimental study of the frequency ω dependence and volume fraction φ dependence of the complex shear modulus of monodisperse emulsions which have been concentrated by an osmotic pressure Π. At a given φ, the elastic storage modulus exhibits a low-frequency plateau dominating the dissipative loss modulus which exhibits a minimum. Above a critical packing fraction we find that both Π(φ) and increase quasilinearly, scaling as where the volume fraction of a random close packing of spheres, and μ is an exponent close to unity. To explain this result, we develop a model of disordered droplets which interact through an effective repulsive anharmonic potential, based on results obtained for a compressed droplet. A simulation based on this model yields a calculated static shear modulus and osmotic pressure Π that are in excellent agreement with the experimental values of and Π.
- Received 24 February 1997
DOI:https://doi.org/10.1103/PhysRevE.56.3150
©1997 American Physical Society