Mechanical & Materials Engineering, Department of
Date of this Version
Results in Engineering 11 (2021) 100278. https://doi.org/10.1016/j.rineng.2021.100278
Contact angle is an important property to quantify the wettability of a solid surface with a liquid, which characterizes interactions of the solid-liquid pair. Generally, to measure contact angle, special instruments such as a goniometer are necessary, but they are not readily available in certain research settings. In this study, an alternative method to measure contact angle based on a Hele-Shaw cell, microscopy imaging, and image processing is suggested. In this method, a liquid drop is injected into a transparent Hele-Shaw cell, the meniscus of the drop is captured in the top or bottom view using a brightfield microscope, and the contact angle is measured from the captured image based on a geometrical model of the drop in the Hele-Shaw cell. The proposed method was tested using two different liquids (deionized water and glycerol) and two different solid surfaces (polydimethylsiloxane [PDMS] and commercial water-repellent-coated glass) with various gap heights of Hele-Shaw cells and validated in comparison with a goniometer. Our results show that the proposed method could measure contact angles reasonably well. Although the concept of the proposed quick-and-dirty contact angle measurement method was proven in this study, there is still room to improve the accuracy and reliability of the proposed method.
Mechanics of Materials Commons, Nanoscience and Nanotechnology Commons, Other Engineering Science and Materials Commons, Other Mechanical Engineering Commons