Growth and self-jumping of single condensed droplet on nanostructured surfaces: A molecular dynamics simulation
JH Pu and SK Wang and J Sun and W Wang and HS Wang, JOURNAL OF MOLECULAR LIQUIDS, 340, 116902 (2021).
Our molecular dynamics simulation demonstrates that the condensed nanodroplets can achieve self-jumping off the nanostructured surface driven by the Laplace pressure difference. The growth and self-jumping dynamics of nanodroplets condensed on the superhydrophobic nanostructured surface with local hydrophilic pinning site are systematically investigated. We reveal that a curvature difference between the droplet top and bottom is generated due to the confinement of the groove walls, which leads to a Laplace pressure difference. It increases with growing droplet and the droplet detaches from the pinning site and finally jumps off when it reaches the threshold against the pinning force from the hydrophilic pinning site. We find that the characteristics of the hydrophilic pinning site shows competitive effects on the whole process, which can be generally divided into incubation and burst stages. Increasing the surface wettability and size of the pinning site promotes the droplet growth but blocks the droplet self-jumping in the meantime due to the increased pinning force. We also find that the droplet-jumping highly depends on the confined portion of the droplet after detaching from the pinning site and its decrease will diminish the excessive surface energy stored in the droplet, which makes the converted kinetic energy insufficient to support the jump-off. The present work sheds light on the fundamental understandings of passive method for condensate removal, self-cleaning, thermal management, etc. (C) 2021 Published by Elsevier B.V.
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