Irreversibility and rate dependence in sheared adhesive suspensions

Experiments and simulations of a non-Brownian suspension of particles demonstrate that weak van der Waals (adhesive) interactions induce rate dependence of the rheological response in oscillatory shear flow, with enhanced particle diffusivities and cluster formations below a critical shear rate, even though the steady shear behavior remains rate-independent. Phase diagrams showing the influence of volume fraction, strain amplitude, and oscillation frequency, for a given Hamaker constant, highlight the connection between irreversibility and suspension rheology.