A1 Journal article (refereed)
Droplet slipperiness despite surface heterogeneity at molecular scale (2024)

Lepikko, S., Morais Jaques, Y., Junaid, M., Backholm, M., Lahtinen, J., Julin, J., Jokinen, V., Sajavaara, T., Sammalkorpi, M., Foster, A. S., & Ras, R. H. A. (2024). Droplet slipperiness despite surface heterogeneity at molecular scale. Nature Chemistry, 16(4), 506-513. https://doi.org/10.1038/s41557-023-01346-3

JYU authors or editors

Publication details

All authors or editors: Lepikko, Sakari; Morais Jaques, Ygor; Junaid, Muhammad; Backholm, Matilda; Lahtinen, Jouko; Julin, Jaakko; Jokinen, Ville; Sajavaara, Timo; Sammalkorpi, Maria; Foster, Adam S.; et al.

Journal or series: Nature Chemistry

ISSN: 1755-4330

eISSN: 1755-4349

Publication year: 2024

Publication date: 23/10/2023

Volume: 16

Issue number: 4

Pages range: 506-513

Publisher: Nature Publishing Group

Publication country: United Kingdom

Publication language: English

DOI: https://doi.org/10.1038/s41557-023-01346-3

Publication open access: Openly available

Publication channel open access: Partially open access channel

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/91825

Additional information: Publisher Correction: Droplet slipperiness despite surface heterogeneity at molecular scale. Nature Chemistry (2023), https://doi.org/10.1038/s41557-023-01401-z.

Abstract

Friction determines whether liquid droplets slide off a solid surface or stick to it. Surface heterogeneity is generally acknowledged as the major cause of increased contact angle hysteresis and contact line friction of droplets. Here we challenge this long-standing premise for chemical heterogeneity at the molecular length scale. By tuning the coverage of self-assembled monolayers (SAMs), water contact angles change gradually from about 10° to 110° yet contact angle hysteresis and contact line friction are low for the low-coverage hydrophilic SAMs as well as high-coverage hydrophobic SAMs. Their slipperiness is not expected based on the substantial chemical heterogeneity of the SAMs featuring uncoated areas of the substrate well beyond the size of a water molecule as probed by metal reactants. According to molecular dynamics simulations, the low friction of both low- and high-coverage SAMs originates from the mobility of interfacial water molecules. These findings reveal a yet unknown and counterintuitive mechanism for slipperiness, opening new avenues for enhancing the mobility of droplets.

Keywords: surfaces; surface chemistry; friction; slipperiness; water

Free keywords: surface chemistry; wetting

Contributing organizations

Ministry reporting: Yes

VIRTA submission year: 2023

JUFO rating: 3