Contact Angle Hysteresis

(find instruments that measure contact angle hysteresis here)

Definition:

Contact Angle Hysteresis is the difference between the measured Advancing and Receding contact angles.

Summary/Description:

The contact angle hysteresis is simply calculated by substracting the measured Advancing (maximum) contact angle with the measured Receding (minimum) contact angle i.e. H = θ_a - θ_r. One can thus say that the hysteresis is the range of stable apparent contact angles that can be measured for the system.

The hysteresis is mainly due to surface roughness, chemical contamination or heterogeneity of the solid substrate, and/or deposition of solutes (surfactants, polymers) from the liquid onto the solid surface.