Kim Dohyung, Lee Minki, Kim Jeong-Hyun, Lee Jinkee
School of Mechanical Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do 16419, Republic of Korea.
Department of Mechanical System Design Engineering, Seoul National University of Science and Technology, Seoul 01811, Republic of Korea.
J Colloid Interface Sci. 2021 Mar 15;586:647-654. doi: 10.1016/j.jcis.2020.10.134. Epub 2020 Nov 3.
Even though lubricant-infused surfaces (LISs) are known to affect the mobility of working fluid depending on the infused lubricant, previous studies have not yet quantified their slippery property. This study proposes the slippery nature of the LIS can be assessed by dynamic contact angles of the working fluid on the LIS and its scaling model.
We measured the apparent dynamic advancing and receding contact angles on a LIS using a modified Wilhelmy plate technique for the first time. Lubricant having different viscosities was infused into the sanded polytetrafluoroethylene surface to fabricate the LIS. The surface was immersed into or withdrawn from an aqueous glycerol-water solution by varying the capillary number and the lubricant viscosity.
The dynamic contact angles on LIS was found to be sensitive to changes in both the lubricant viscosity and the capillary number. The cube of the dynamic contact angles on the LIS was proportional to θ~Ca, which follows a conventional hydrodynamic theory. In addition, the decreasing lubricant viscosity shifted the cube of the dynamic contact angles to high capillary numbers. Our dynamic contact angle data coincided with the prediction from a scaling law derived in this study.
尽管已知注入润滑剂的表面（LISs）会根据注入的润滑剂影响工作流体的流动性，但先前的研究尚未对其滑爽特性进行量化。本研究提出，LIS的滑爽性质可以通过工作流体在LIS上的动态接触角及其缩放模型来评估。
我们首次使用改进的Wilhelmy板技术测量了LIS上的表观动态前进和后退接触角。将具有不同粘度的润滑剂注入磨砂聚四氟乙烯表面以制造LIS。通过改变毛细管数和润滑剂粘度，将表面浸入或从甘油水溶液中抽出。
发现LIS上的动态接触角对润滑剂粘度和毛细管数的变化都很敏感。LIS上动态接触角的立方与θ~Ca成正比，这遵循传统的流体动力学理论。此外，润滑剂粘度的降低将动态接触角的立方转移到高毛细管数。我们的动态接触角数据与本研究得出的缩放定律的预测结果一致。
