Superhydrophobic surfaces: a model approach to predict contact angle and surface energy of soil particles

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Bachmann, J. and McHale, G., 2009. Superhydrophobic surfaces: a model approach to predict contact angle and surface energy of soil particles. European Journal of Soil Science, 60 (3), pp. 420-430.

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Abstract

Wettability of soil affects a wide variety of processes including infiltration, preferential flow and surface runoff. The problem of determining contact angles and surface energy of powders, such as soil particles, remains unsolved. So far, several theories and approaches have been proposed, but formulation of surface and interfacial free energy, as regards its components, is still a very debatable issue. In the present study, the general problem of the interpretation of contact angles and surface free energy on chemically heterogeneous and rough soil particle surfaces is evaluated by a reformulation of the Cassie-Baxter equation, assuming that the particles are attached on to a plane and rigid surface. Compared with common approaches, our model considers a roughness factor that depends on the Young’s Law contact angle determined by the surface chemistry. Results of the model are discussed and compared with independent contact angle measurements using the Sessile Drop and the Wilhelmy Plate methods. Based on contact angle data, the critical surface tension of the grains were determined by the method proposed by Zisman.

Item Type:

Journal article

Description:

The definitive version is available at www3.interscience.wiley.com

Publication Title:

European Journal of Soil Science

Creators:

Bachmann, J. and McHale, G.

Publisher:

Wiley-Blackwell (ELF)

Date:

2009