Quantitative Characterization Of Surface Wettability By Friction Force

The adhesion of a water drop on a solid surface is usually qualitatively characterized by sliding angle (SA). However, SA cannot distinguish the surfaces on which water droplet sticks. Here, we report a feasible technique, MPCP, to quantitatively characterize the surface wettability by measuring the liquid-solid friction force. Using a microstripe surface, MPCP technique is demonstrated to be able to precisely distinguish the surfaces with strong adhesion to water droplets that conventional SA cannot distinguish. Moreover, MPCP possess the abilities to reveal the detailed features of a friction process (static friction, kinetic friction and stick-slip behaviors) and to study the influencing factors for a liquidsolid friction. The MPCP technique has the potential to be widely used in many applications, such as surface engineering, biomedicine and microfluidics.