Design of Fluoro-Free Surfaces Super-Repellent to Low-Surface-Tension Liquids

William S.Y. Wong*, Mariia S. Kiseleva, Shaochen Zhou, Muhammad Junaid, Leena Pitkänen, Robin H.A. Ras*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

8 Citations (Scopus)
59 Downloads (Pure)

Abstract

Super-liquid-repellent surfaces feature high liquid contact angles and low sliding angles find key applications in anti-fouling and self-cleaning. While repellency for water is easily achieved with hydrocarbon functionalities, repellency for many low-surface-tension liquids (down to 30 mN m−1) still requires perfluoroalkyls (a persistent environmental pollutant and bioaccumulation hazard). Here, the scalable room-temperature synthesis of stochastic nanoparticle surfaces with fluoro-free moieties is investigated. Silicone (dimethyl and monomethyl) and hydrocarbon surface chemistries are benchmarked against perfluoroalkyls, assessed using model low-surface-tension liquids (ethanol–water mixtures). It is discovered that both hydrocarbon- and dimethyl-silicone-based functionalization can achieve super-liquid-repellency down to 40–41 mN m−1 and 32–33 mN m−1, respectively (vs 27–32 mN m−1 for perfluoroalkyls). The dimethyl silicone variant demonstrates superior fluoro-free liquid repellency likely due to its denser dimethyl molecular configuration. It is shown that perfluoroalkyls are not necessary for many real-world scenarios requiring super-liquid-repellency. Effective super-repellency of different surface chemistries against different liquids can be adequately predicted using empirically verified phase diagrams. These findings encourage a liquid-centric design, i.e., tailoring surfaces for target liquid properties. Herein, key guidelines are provided for achieving functional yet sustainably designed super-liquid-repellency.

Original languageEnglish
Article number2300306
JournalAdvanced Materials
Volume35
Issue number29
Early online date13 Apr 2023
DOIs
Publication statusPublished - 20 Jul 2023
MoE publication typeA1 Journal article-refereed

Keywords

  • polar and dispersive interactions
  • predicting superwettability
  • super-liquid-repellent surfaces
  • superhydrophobic materials
  • surface chemistry

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