Dynamics of Droplets Impacting on Aerogel, Liquid Infused, and Liquid-Like Solid Surfaces

Jack Dawson, Samual Coaster, Rui Han, Johannes Gausden, Hongzhong Lui, Glen McHale, Chen Jinju

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

Droplets impacting superhydrophobic surfaces have been extensively studied due to their compelling scientific insights and important industrial applications. In these cases, the commonly reported impact regime was that of complete rebound. This impact regime strongly depends on the nature of the superhydrophobic surface. Here, we report the dynamics of droplets impacting three hydrophobic slippery surfaces, which have fundamental differences in normal liquid adhesion, and lateral static and kinetic liquid friction. For an air cushion-like (super)hydrophobic solid surface (Aerogel) with low adhesion and low static and low kinetic friction, complete rebound can start at a very low Weber (We) number (~1). For slippery liquid-infused porous (SLIP) surfaces with high adhesion and low static and low kinetic friction, complete rebound only occurs at a much higher We number (>5). For a slippery omniphobic covalently attached liquid-like (SOCAL) solid surface, with high adhesion and low static friction similar to SLIPS, but higher kinetic friction, complete rebound was not observed, even for We as high as 200. Furthermore, the droplet ejection volume after impacting the Aerogel surface is 100% across the whole range of We numbers tested compared to other surfaces. In contrast, droplet ejection for SLIPs was only observed consistently when We was above 5-10. For SOCAL, 100% (or near 100%) ejection volume was not observed even at the highest We number tested here (~200). This suggests droplets impacting our (super)hydrophobic Aerogel and SLIPS lose less kinetic energy. These insights into the differences between normal adhesion and lateral friction properties can be used to inform the selection of surface properties to achieve the most desirable droplet impact characteristics to fulfil a wide range of applications, such as de-icing, inkjet printing, and microelectronics.

See also correction at https://pubs.acs.org/doi/10.1021/acsami.3c16610
Original languageEnglish
JournalACS Applied Materials & Interfaces
Early online date29 Dec 2022
DOIs
Publication statusE-pub ahead of print - 29 Dec 2022

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