Direct Observation of Gas Meniscus Formation on a Superhydrophobic SurfaceShow others and affiliations
2019 (English)In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 13, no 2, p. 2246-2252Article in journal (Refereed) Published
Abstract [en]
The formation of a bridging gas meniscus via cavitation or nanobubbles is considered the most likely origin of the submicrometer long-range attractive forces measured between hydrophobic surfaces in aqueous solution. However, the dynamics of the formation and evolution of the gas meniscus is still under debate, in particular, in the presence of a thin air layer on a superhydrophobic surface. On superhydrophobic surfaces the range can even exceed 10 μm. Here, we report microscopic images of the formation and growth of a gas meniscus during force measurements between a superhydrophobic surface and a hydrophobic microsphere immersed in water. This is achieved by combining laser scanning confocal microscopy and colloidal probe atomic force microscopy. The configuration allows determination of the volume and shape of the meniscus, together with direct calculation of the Young-Laplace capillary pressure. The long-range attractive interactions acting on separation are due to meniscus formation and volume growth as air is transported from the surface layer.
Place, publisher, year, edition, pages
2019. Vol. 13, no 2, p. 2246-2252
Keywords [en]
AFM colloidal probe, capillary forces, laser scanning confocal microscopy, superhydrophobicity, wetting
National Category
Natural Sciences
Identifiers
URN: urn:nbn:se:ri:diva-37821DOI: 10.1021/acsnano.8b08922PubMedID: 30707561Scopus ID: 2-s2.0-85061527266OAI: oai:DiVA.org:ri-37821DiVA, id: diva2:1292973
2019-03-012019-03-012023-06-08Bibliographically approved