Experimental simulation of capillary effect on rough flat surfaces

The movement of the liquid column inside the slit was utilized to experimentally simulate the characteristics of the capillary force per unit length for different rough flat surfaces. The movement of the liquid column was achieved by continuously changing the slit interval. The maximum climb height and contact angle of the liquid column were observed during this process to study the relationship between capillary force and contact surface roughness. Based on the assumption that the microstructures on the rough surfaces are of the same form and continuously and uniformly distributed, it is shown that the capillary force per unit length under homogeneous wetting is independent of the roughness. For heterogeneous wetting, the capillary force per unit length is positively correlated with the roughness. The results also indicate that the appearance of contact line pinning is caused by insufficient capillary force along the direction of liquid column movement. (c) 2021 Published by Elsevier B.V. on behalf of Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences.

Automated summary

The relationship between capillary force and contact surface roughness was studied by investigating the movement of the liquid column inside a slit. It was found that under homogeneous wetting, capillary force is independent of the roughness, while under heterogeneous wetting, capillary force is positively correlated with roughness.