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Contact angle hysteresis

2022; Elsevier BV; Volume: 59; Linguagem: Inglês

10.1016/j.cocis.2022.101574

1879-0399

Hans‐Jürgen Butt, Jie Liu, Kaloian Koynov, Benedikt B. Straub, Chirag Hinduja, Ilia Roismann, Rüdiger Berger, Xiaomei Li, Doris Vollmer, W. Steffen, Michael Kappl,

Fluid Dynamics and Thin Films

In thermodynamic equilibrium, the contact angle is related by Young's equation to the interfacial energies. Unfortunately, it is practically impossible to measure the equilibrium contact angle. When for example placing a drop on a surface its contact angle can assume any value between the advancing Θa and receding Θr contact angles, depending on how the drop is placed. Θa − Θr is called contact angle hysteresis. Contact angle hysteresis is essential for our daily life because it provides friction to drops. Many applications, such as coating, painting, flotation, would not be possible without contact angle hysteresis. Contact angle hysteresis is caused by the nanoscopic structure of the surfaces. Here, we review our current understanding of contact angle hysteresis with a focus on water as the liquid. We describe appropriate methods to measure it, discuss the causes of contact angle hysteresis, and describe the preparation of surfaces with low contact angle hysteresis.