Universal mechanism of shear thinning in supercooled liquids

Abstract

Soft glassy materials experience a significant reduction in viscosity $\eta$ when subjected to shear flow, known as shear thinning. This phenomenon is characterized by a power-law scaling of $\eta$ with the shear rate $\dot{\gamma }$, $\eta \propto {\dot{\gamma }}^{-\nu }$, where the exponent $\nu$ is typically around $0.7$ to $0.8$ across different materials. Two decades ago, the mode coupling theory (MCT) suggested that shear thinning occurs due to the advection. However, it predicts too large $\nu =1$ (> $0.7$ to $0.8$) and overestimates the onset shear rate by orders of magnitude. Recently, it was claimed that a minute distortion of the particle configuration is responsible for shear thinning. Here we extend the MCT to include the distortion, and find that both advection and distortion contribute to shear thinning, but the latter is dominant. Our formulation works quantitatively for several different glass formers. We explain why shear thinning is universal for many glassy materials.

14pages, 12figures, 1table

References in corpus (11)

• Inhomogeneous Mode-Coupling Theory and Growing Dynamic Length in Supercooled Liquids
• Three-dimensional imaging of colloidal glasses under steady shear
• The glass transition of dense fluids of hard and compressible spheres
• Shear-transformation-zone theory of plastic deformation near the glass transition
• Glass Rheology: From mode-coupling theory to a dynamical yield criterion
• A mode coupling theory for Brownian particles in homogeneous steady shear flow
• Finite size effects in the dynamics of glass-forming liquids
• Multiple length and time scales of dynamic heterogeneities in model glass-forming liquids: A systematic analysis of multi-point and multi-time correlations
• Schematic Mode Coupling Theory of Glass Rheology: Single and Double Step Strains
• Glassy phases of the Gaussian Core Model
• Quantification of the volume-fraction reduction of sheared fragile glass-forming liquids and its impact on rheology

Cited by in corpus (4)

• Viscosity of polymer melts using non-affine theory based on vibrational modes
• Connecting Shear Thinning and Dynamic Heterogeneity in Supercooled Liquids by Localized Elasticity
• Microscopic Basis for Recovery Rheology and the Nonequilibrium Structure,Yielding, and Flow of Dense Particle Suspensions
• Understanding Flow Behaviors of Supercooled Liquids by Embodying Solid-Liquid Duality at Particle Level