Xiang Yijie, Fulmek Paul, Platz Daniel, Schmid Ulrich
Institute of Sensor and Actuator Systems, Vienna University of Technology, Vienna 1040, Austria.
Langmuir. 2022 Feb 1;38(4):1631-1637. doi: 10.1021/acs.langmuir.1c03202. Epub 2022 Jan 20.
In this work, we investigate the change of contact angle (CA) of a water droplet during evaporation on a Teflon AF1600 surface in the temperature range between 20 and 80 °C under standard laboratory conditions. An almost constant initial CA and a significant increase of the stabilized CA have been observed. The results reveal a temperature-dependent CA change, mainly due to water adsorption on the solid surface. Soaking experiments indicate that besides adsorption, a temperature-independent friction-like force contributes to the pinning of triple-line and therefore to the CA change. We propose an adsorption coverage parameter and a friction-like force to describe the CA change. Furthermore, we describe a reproducible process to produce smooth and homogeneous Teflon AF1600 thin films, minimizing the influence of roughness and local heterogeneity on the CA.
在这项工作中，我们研究了在标准实验室条件下，温度范围为20至80°C时，水滴在聚四氟乙烯AF1600表面蒸发过程中接触角（CA）的变化。观察到初始接触角几乎恒定，且稳定后的接触角显著增加。结果表明，接触角的变化与温度有关，主要是由于水在固体表面的吸附。浸泡实验表明，除吸附作用外，一种与温度无关的类似摩擦力的力有助于三线钉扎，从而导致接触角的变化。我们提出了一个吸附覆盖参数和一个类似摩擦力的力来描述接触角的变化。此外，我们描述了一种可重复的方法来制备光滑均匀的聚四氟乙烯AF1600薄膜，将粗糙度和局部不均匀性对接触角的影响降至最低。
