Through-drop imaging of moving contact lines and contact areas on opaque water-repellent surfaces

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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

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en

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10

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Soft Matter, Volume 19, issue 13, pp. 2350-2359

Abstract

A myriad of natural surfaces such as plant leaves and insect wings can repel water and remain unwetted inspiring scientists and engineers to develop water-repellent surfaces for various applications. Those natural and artificial water-repellent surfaces are typically opaque, containing micro- and nano-roughness, and their wetting properties are determined by the details at the actual liquid-solid interface. However, a generally applicable way to directly observe moving contact lines on opaque water-repellent surfaces is missing. Here, we show that the advancing and receding contact lines and corresponding contact area on micro- and nano-rough water-repellent surfaces can be readily and reproducibly quantified using a transparent droplet probe. Combined with a conventional optical microscope, we quantify the progression of the apparent contact area and apparent contact line irregularity in different types of superhydrophobic silicon nanograss surfaces. Contact angles near 180° can be determined with an uncertainty as low as 0.2°, that a conventional contact angle goniometer cannot distinguish. We also identify the pinning/depinning sequences of a pillared model surface with excellent repeatability and quantify the progression of the apparent contact interface and contact angle of natural plant leaves with irregular surface topography.

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| openaire: EC/H2020/725513/EU//SuperRepel

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Vieira, A F, Cui, W, Jokinen, V, Ras, R H A & Zhou, Q 2023, 'Through-drop imaging of moving contact lines and contact areas on opaque water-repellent surfaces', Soft Matter, vol. 19, no. 13, pp. 2350-2359. https://doi.org/10.1039/D2SM01622B