Thixotropy
shear thinning property / From Wikipedia, the free encyclopedia
Thixotropy is the property of certain gels or fluids that are viscous (thick) under normal conditions, but flow (become thin, less viscous) when shaken, agitated, or otherwise stressed.
In more technical language: some Non-Newtonian fluids show a change in viscosity; the longer the fluid undergoes shear stress, the lower its viscosity. A thixotropic fluid is a fluid which takes a finite time to attain equilibrium viscosity when introduced to a step change in shear rate. Many gels and colloids are thixotropic materials, exhibiting a stable form at rest but becoming fluid when agitated.
Some fluids are anti-thixotropic: constant shear stress for a time causes an increase in viscosity or even solidification. Constant shear stress can be applied by shaking or mixing. They are much less common.