Elasticity and dynamics of particle gels in non-newtonian melts

We investigate the relation between structure and viscoelasticity of model polymer nanocomposite systems based on a mixture of spherical nanoparticles and different polymer matrices. These composites exhibit a strong time-dependence of the linear elastic and viscous moduli for filler volume fractions above a critical threshold. Despite the complexity of the rheological response, we can scale the viscoelastic properties of the hybrids by splitting their elasticity and dynamics Into the independent responses of the suspending polymer melt and that of an elastic particle network. We show that the elasticity of the particle network exhibits critical behavior at the percolation threshold. Our analysis is expected to be useful for understanding the behavior of other complex fluids where the elasticity of the components may be superimposed.