Effects of liquid surface tension on gas capillaries and capillary forces at superamphiphobic surfaces

Mimmi Eriksson; Per M Claesson; Mikael Järn; Viveca Wallqvist; Mikko Tuominen; Michael Kappl; Hannu Teisala; Doris Vollmer; Joachim Schoelkopf; Patrick A C Gane; Jyrki M Mäkelä; Agne Swerin

doi:10.1038/s41598-023-33875-9

Effects of liquid surface tension on gas capillaries and capillary forces at superamphiphobic surfaces

Sci Rep. 2023 Apr 26;13(1):6794. doi: 10.1038/s41598-023-33875-9.

Authors

Mimmi Eriksson^{1

2}, Per M Claesson², Mikael Järn¹, Viveca Wallqvist¹, Mikko Tuominen¹, Michael Kappl³, Hannu Teisala³, Doris Vollmer³, Joachim Schoelkopf⁴, Patrick A C Gane^{5

6}, Jyrki M Mäkelä⁷, Agne Swerin^{8

9}

Affiliations

¹ RISE Research Institutes of Sweden, 11486, Stockholm, Sweden.
² Division of Surface and Corrosion Science, Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, 10044, Stockholm, Sweden.
³ Department of Physics at Interfaces, Max Planck Institute for Polymer Research, 55128, Mainz, Germany.
⁴ Omya International AG, 4665, Oftringen, Switzerland.
⁵ Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, 00076, Aalto, Finland.
⁶ Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11000, Belgrade, Serbia.
⁷ Physics Unit, Aerosol Physics Laboratory, Tampere University, 33014, Tampere, Finland.
⁸ Division of Surface and Corrosion Science, Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, 10044, Stockholm, Sweden. agne.swerin@kau.se.
⁹ Department of Engineering and Chemical Sciences, Karlstad University, 65188, Karlstad, Sweden. agne.swerin@kau.se.

Abstract

The formation of a bridging gas capillary between superhydrophobic surfaces in water gives rise to strongly attractive interactions ranging up to several micrometers on separation. However, most liquids used in materials research are oil-based or contain surfactants. Superamphiphobic surfaces repel both water and low-surface-tension liquids. To control the interactions between a superamphiphobic surface and a particle, it needs to be resolved whether and how gas capillaries form in non-polar and low-surface-tension liquids. Such insight will aid advanced functional materials development. Here, we combine laser scanning confocal imaging and colloidal probe atomic force microscopy to elucidate the interaction between a superamphiphobic surface and a hydrophobic microparticle in three liquids with different surface tensions: water (73 mN m^-1), ethylene glycol (48 mN m^-1) and hexadecane (27 mN m^-1). We show that bridging gas capillaries are formed in all three liquids. Force-distance curves between the superamphiphobic surface and the particle reveal strong attractive interactions, where the range and magnitude decrease with liquid surface tension. Comparison of free energy calculations based on the capillary menisci shapes and the force measurements suggest that under our dynamic measurements the gas pressure in the capillary is slightly below ambient.

Grants and funding

FID15-0029/Stiftelsen för Strategisk Forskning