Unified model for full-stage shear thickening via surface chemistry and friction

Shear thickening fluid exhibits complex properties in a wide range of external conditions, leading to the significance for probing its state-transition property at the molecular level. Here, we propose a constitutive model that unifies the three rheological stages of shear thinning, shear thickening, and secondary shear thinning by considering the short-range attractive forces governed by particle surface chemistry in shear thickening dense suspensions. The proposed model reproduces the secondary shear thinning phenomenon precisely and predicts the evolution of cluster number, size, and dispersion with a marked error reduction. Besides, based on the proposed model, the distribution of particles can be divided into isolated, uniform-aggregated, and overaggregated states according to the dissipative particle dynamics simulation results. This model provides a framework to design rheological behavior via particle surface chemistry, bridge the relationship between microstructure and macroscopic performance at various scales, and accelerate the understanding to the state-transition phenomenon in shear thickening dense suspension.