TY - JOUR
T1 - Slippery liquid-infused porous surfaces
T2 - The effect of oil on the water repellence of hydrophobic and superhydrophobic soils
AU - McCerery, Rebecca
AU - Woodward, John
AU - McHale, Glen
AU - Winter, Kate
AU - Armstrong, Steven
AU - Orme, Bethany V.
N1 - Funding Information:
We would like to acknowledge Dr G.G. Wells and Dr P. Agrawal for their advice, technical support and guidance. We also thank the two anonymous reviewers who provided helpful comments. R. McCerery would like to acknowledge Northumbria University at Newcastle for financial support.
PY - 2021/3/1
Y1 - 2021/3/1
N2 - 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. Highlights: We model oil contamination on a hydrophobic model soil as a mechanism for creating SLIPS. Soil SLIPS have implications for water-shedding, oil spill remediation and earth processes. Our model soils exhibit extreme water-shedding, illustrated by low water droplet sliding angles. This is the first physical modelling observation of SLIPS arising from hydrophobic soil.
AB - 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. Highlights: We model oil contamination on a hydrophobic model soil as a mechanism for creating SLIPS. Soil SLIPS have implications for water-shedding, oil spill remediation and earth processes. Our model soils exhibit extreme water-shedding, illustrated by low water droplet sliding angles. This is the first physical modelling observation of SLIPS arising from hydrophobic soil.
KW - earth processes
KW - hydrophobicity
KW - oil contamination
KW - sediments
KW - slippery liquid-infused porous surfaces
KW - soil systems
KW - soil water repellence
KW - superhydrophobicity
UR - http://www.scopus.com/inward/record.url?scp=85092575642&partnerID=8YFLogxK
U2 - 10.1111/ejss.13053
DO - 10.1111/ejss.13053
M3 - Article
AN - SCOPUS:85092575642
VL - 72
SP - 963
EP - 978
JO - Journal of Soil Sciences
JF - Journal of Soil Sciences
SN - 0022-4588
IS - 2
ER -