Time Strain Superposition in Nanoparticle Organic Hybrids

We report frequency-dependent shear rheology of dense suspensions of hairy nanoparticles. These materials mimic soft glass materials in many ways including a yield stress, slow dynamics and divergence of the viscosity. We find that measurements performed over a limited range of frequencies and varying shear strains can be superposed onto a master curve that spans more than 22 decades in frequency. SGR model predicts consistent result with experimental data only at strains lower than yield strain. For larger strains, the strain-dependent horizontal shift factor is Surprisingly fit well by the empirical WLF equation for amorphous polymers, with temperature replaced by strain.