title: Estimation of solid-liquid interfacial tension using curved surface of a soft solid.
abstract: Unlike liquids, for crystalline solids the surface tension is known to be different from the surface energy. However, the same cannot be said conclusively for amorphous materials like soft cross-linked elastomers. To resolve this issue we have introduced here a direct method for measuring solid-liquid interfacial tension by using the curved surface of a solid. In essence, we have used the inner surface of tiny cylindrical channels embedded inside a soft elastomeric film for sensing the effect of the interfacial tension. When a liquid is inserted into the channel, because of wetting-induced alteration in interfacial tension, its thin wall deflects considerably; the deflection is measured with an optical profilometer and analyzed using the Föppl-von Kármán equation. We have used several liquids and cross-linked poly(dimethylsiloxane) as the solid to show that the estimated values of the solid-liquid interfacial tension matches with the corresponding solid-liquid interfacial energy reasonably well.
authors.affiliation: Department of Chemical Engineering, Indian Institute of Technology, Kanpur 208016, India;
authors.forename: Subrata
authors.initials: S
authors.lastname: Mondal
authors.affiliation: Department of Chemical Engineering, Indian Institute of Technology, Kanpur 208016, India;
authors.forename: Monmee
authors.initials: M
authors.lastname: Phukan
authors.affiliation: Department of Chemical Engineering, Indian Institute of Technology, Kanpur 208016, India; Center for Environmental Science and Engineering, Indian Institute of Technology, Kanpur 208016, India; Leibniz Institute for New Materials, 66123 Saarbruecken, Germany aghatak@iitk.ac.in.
authors.forename: Animangsu
authors.initials: A
authors.lastname: Ghatak
keywords: bulging; soft solid; surface energy; surface tension; wetting