Predicting bio-inspired candidate surfaces with superomniphobic characteristics

Lempesis, Nikolaos (Plastics Innovation Competence Center, Fribourg, Switzerland ; School of Engineering and Architecture (HEIA-FR), HES-SO // University of Applied Sciences Western Switzerland) ; Janka, Ales (School of Engineering and Architecture (HEIA-FR), HES-SO // University of Applied Sciences Western Switzerland) ; Gnatiuk, Oksana (Department of Mathematics and Computer Science, Eindhoven University of Technology, Eindhoven, The Netherlands) ; Eijndhoven, Stef J. L. (School of Engineering and Architecture (HEIA-FR), HES-SO // University of Applied Sciences Western Switzerland) ; Koopmans, Rudolf J. (Plastics Innovation Competence Center, Fribourg, Switzerland ; School of Engineering and Architecture (HEIA-FR), HES-SO // University of Applied Sciences Western Switzerland)

We report the development and application of a refined version of the classical Cassie-Baxter wetting model for the prediction of surface topographies with superomniphobic traits. The sagging height defined through the capillary length was utilized to assess the relation between a curved liquid-air interface and the surface texture. The wettability, expressed in terms of the static apparent contact angle, was quantified for single- and double-scale surface topographies and for three representative liquids and the results were compared to those of the classical Cassie-Baxter model. Of the three single-scale topographies considered in this work, the fiber case exhibited the highest contact angle across length scales of surface topographies, whereas decreasing the length scale of surface patterns from a few hundreds of micrometers to a few hundreds of nanometers led to contact angle increase by 15%–20%. A generic expression for modeling multiscale hierarchical roughness of arbitrarily large multiplicity n was derived and applied. Multiscale hierarchical roughness was corroborated to be a promising way for achieving enhanced liquid repellency. Double-scale roughness was more efficient when the two length scales differed in size by at least one order of magnitude. The 'fiber on sinusoid' hierarchical topography exhibiting re-entrant geometry yielded contact angles over 150° for all considered wetting liquids.


Article Type:
scientifique
Faculty:
Ingénierie et Architecture
School:
HEIA-FR
Institute:
iCoSys - Institut des systèmes complexes
IRAP - Institut de recherche appliquée en plasturgie
Date:
2020-05
Pagination:
19 p.
Published in:
Surface Topography: Metrology and Properties
Numeration (vol. no.):
2020, no. 8, article no. 025021
DOI:
ISSN:
2051-672X
Appears in Collection:

Note: The file is under embargo until: 2021-05-31


 Record created 2020-06-02, last modified 2020-06-16

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