Slippery Liquid-Infused Porous Surfaces: The Effect of Oil on the Water Repellency of Hydrophobic and Superhydrophobic Soils

Rebecca McCerery (Lead Author), John Woodward, Glen McHale, Kate Winter, Steven Armstrong, Bethany V. Orme

Research output: Contribution to journalArticlepeer-review

Abstract

Soil wettability is important for understanding a wide range of earth system processes, from agricultural productivity to debris flows and sediment fan formation. However, there is limited research considering how soil–water interactions, where the soil grains are naturally hydrophobic, might change in the presence of oil from natural hydrocarbon leakage or oil spills. Here we show how slippery liquid‐infused porous surfaces (SLIPS) apply to hydrophobic soils, by physical modelling of surfaces of different grain sizes and examining their interactions with water before and after impregnation with silicone oil. Using contact and sliding angle measurements and laser scanning fluorescence confocal microscopy, we demonstrate that soil SLIPS can be created with thick oil layers and thin conformal oil layers on median grain sizes of 231 μm and 32 μm, respectively. Until now, SLIPS have only been observed in human‐made materials and biological surfaces. The mechanisms reported here demonstrate that SLIPS can occur in natural granular materials, providing a new mechanism for water‐shedding in soil and sediment systems. Furthermore, the water‐shedding properties may be long lasting as conformal oil layers are stabilized by capillary forces. These results have important implications for understanding soil physics and mechanics where oil is present in a soil, and for agricultural hydrophobicity on shallow slopes.
Original languageEnglish
JournalEuropean Journal of Soil Science
Early online date23 Sep 2020
DOIs
Publication statusE-pub ahead of print - 23 Sep 2020

Keywords

  • Earth Processes
  • Hydrophobicity
  • oil contamination
  • sediments
  • Slippery liquid-infused porous surface
  • soil systems
  • soil water repellency
  • superhydrophobicity

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