Shear Thickening

While most suspensions and polymer structured mate­rials are shear thinning, some materials can also show shear thickening behavior where viscosity increases with increasing shear rate or shear stress. This phenomenon is often called dilatancy and although this refers to a specific mechanism for shear thickening associated with a vol­ume increase, the terms are often used interchangeably.

In most cases, shear thickening occurs over a decade of shear rates and there can be a region of shear thin­ning at lower and higher shear rates. Usually, dispersions or particulate suspensions with a high concentration of solid particles exhibit shear thickening.