Shear Thickening and Scaling of the Elastic Modulus in a Fractal Colloidal System with Attractive Interactions - Condensed Matter > Soft Condensed Matter

Abstract: Dilute oil dispersions of fractal carbon black particles with attractive Vander Waals interactions display continuous shear thickening followed by shearthinning at high shear rates. The shear thickening transition occurs at$\dot\gamma {c}\approx 10^{2}-10^{3}s^{-1}$ and is driven by hydrodynamicbreakup of clusters. Pre-shearing dispersions at shear rates$\dot\gamma>\dot\gamma {c}$ produces enhanced-modulus gels where $G- \sim\sigma {pre-shear}^{1.5-2}$ and is directly proportional to the residual stressin the gel measured at a fixed sample age. The observed data can be accountedfor using a simple scaling model for the breakup of fractal clusters undershear stress.

Author: Chinedum O. Osuji, Chanjoong Kim, David A. Weitz

Source: https://arxiv.org/