The features of the contact angle evaluation at the nanoscale

Burian, S. A., Hrebnov, O. A., Sysoev, V. M., Isaiev, M. V. (2018). The features of the contact angle evaluation at the nanoscale. Bulletin of Taras Shevchenko National University of Kyiv. Physics and Mathematics(3), 83–88. https://doi.org/10.17721/1812-5409.2018/3.12

The information regarding the wetting characteristic is important in various aspects of surface science. One of the markers that more frequently uses for describing of wetting characteristics is the wetting angle. Even an estimation of the wetting at the macroscale is a tricky issue, because of the hysteresis between receding and advancing values presence. In the same time, the situation is more complicated for a nanoscopic droplet due to the tangible thickness of the interphase region, what causes an uncertainty of the dividing surface determination, as a consequence it causes an uncertainty of the contact angle determination. In this work using methods molecular dynamics we performed simulations of the cylindrical nanodprolet and the layer of the argon fluid. The density maps and the maps of tension tensor were also measured. Basing on the analysis of the maps within the framework of the Gibbs approach, the equimolar surfaces and the surfaces of tension on the liquid-gas interface and the liquid-solid interface was determined. For the cylindrical nanodroplet, the equilibrium contact wetting angles formed by the corresponding dividing surfaces were estimated. The measured angles differ by more than 10%.Key words: wetting, nanodroplet, surface tension, surfaces of tension, hydrophobic forces.Pages of the article in the issue: 83 - 88Language of the article: Ukrainian