The shape of yield stress filaments on a surface

A liquid filament spreads on a surface until it reaches equilibrium. In the case of yield stress (a.k.a. viscoplastic) fluids, the dynamics and the final static shape are determined by the surface tension, gravity, solid surface properties, and the liquid's rheological properties. We experimentally show how the yield stress dictates the final shape of gently deposited yield stress filaments on a surface. We also present a counterpart theory based on viscoplastic lubrication theory and compare the results with the experiments. 

The present work provides information on the physics of capillary flows of complex fluids used in a wide range of applications such as coating and 3D printing.