Structurized surface layers of normal alkanes

Author: Altoiz B.   Kiriyan S.  

Publisher: Springer Publishing Company

ISSN: 1062-0125

Source: Journal of Engineering Physics and Thermophysics, Vol.83, Iss.3, 2010-07, pp. : 650-656

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Abstract

The elevated viscosity of micron interlayers of certain normal alkanes compared to their viscosity in the "volume" is determined experimentally in shear flow using a rotational viscometer. The observed difference is considered to be caused by the manifestation, in such interlayers, of structural inhomogeneity due to the presence of structurized polymolecular surface layers on the substrates bounding them. The structural parameters of such layers, i.e., their equilibrium initial thickness and "hydrodynamic strength," are calculated in the model of a constant-viscosity layer. The measured effective viscosity of the interlayers diminishes with growth in the shear-flow velocity, which is attributed to the "cutting" of the structurized layer. Surfactant doping of the liquids leads to an increase in the effective viscosity of the interlayers, which is produced by the strengthening of the layer structure.