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arXiv · 2112.09770

Controlling the dewetting morphologies of thin liquid films by switchable substrates

Stefan Zitz·Andrea Scagliarini·Jens Harting
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Abstract

Switchable and adaptive substrates emerged as valuable tools for the control of wetting and actuation of droplet motion. Here we report a computational study of the dynamics of an unstable thin liquid film deposited on a switchable substrate, modelled with a space and time varying contact angle. With a static pattern, all the fluid is drained into droplets located around contact angle minima, whereas for a sufficiently large rate of wettability variation a state consisting of metastable rivulets is observed. A criterion discriminating whether rivulets can be observed or not is identified in terms of a single dimensionless parameter. Finally, we show and explain theoretically how the film rupture times, droplet shape and rivulet life time depend on the pattern wavelength and speed.

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Stefan Zitz, Andrea Scagliarini, Jens Harting. 2021-12-17. Controlling the dewetting morphologies of thin liquid films by switchable substrates. https://doi.org/10.1103/physrevfluids.8.l122001

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