Research into the boundary viscosity of volatile liquids by the blow-off method

• Published in: Journal of colloid and interface science 1978-01, Vol.67 (3), p.465-476
• Main Authors: Depuaguin, B.V, Karasev, V.V, Starov, V.M, Khromova, E.N
• Format: Article
• Language: English
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/0021-9797(78)90236-9

A blow-off method was developed earlier, allowing the boundary viscosity to be determined as a function of the distance to a solid substrate. This method was used to study the boundary viscosity of a number of organic liquids and oils. In this paper we present a modification, of the method making it applicable to a wider range of objects including volatile liquids. An essentially new theory has been suggested, taking into account not only the flow of a film but also its evaporation with gas being blown through a plane-parallel channel. The theory allows one to find the dependence of the viscosity on the distance to the substrate h, with η being a continuous function of h. A procedure is outlined for computer calculation of experimental data. A computer program has been compiled for calculating the dependence of the viscosity η on h. The obtained experimental data on the boundary viscosity of hexadecane show that the viscosity in a layer 40–200 Å thick is lower than that in the bulk.