Eur. Phys. J. E 9, 47-53 (2002)
DOI: 10.1140/epje/i2001-10112-9

Nanorheology: An investigation of the boundary condition at hydrophobic and hydrophilic interfaces

C. Cottin-Bizonne¹, S. Jurine¹, J. Baudry¹, J. Crassous², F. Restagno^{1, 3} and É. Charlaix<sup>1

1</sup>  Département de Physique des Matériaux (UMR 5586), Université Lyon I, 43 bd du 11 Novembre 1918, 69622 Villeurbanne Cedex, France
²  Laboratoire de Physique (UMR 5672), ENS-Lyon, 46 allée d'Italie, 69364 Lyon Cedex 07, France
³  Laboratoire de Physique des Solides (UMR 8502), Bât. 510 - Campus Universitaire, 91405 Orsay Cedex, France (Present address.)

ccottin@dpm.univ-lyon1.fr

(Received 21 December 2001 and Received in final form 3 August 2002 / Published online: 22 November 2002)

Abstract
It has been shown that the flow of a simple liquid over a solid surface can violate the so-called no-slip boundary condition. We investigate the flow of polar liquids, water and glycerol, on a hydrophilic Pyrex surface and a hydrophobic surface made of a Self-Assembled Monolayer of OTS (octadecyltrichlorosilane) on Pyrex. We use a Dynamic Surface Force Apparatus (DSFA) which allows one to study the flow of a liquid film confined between two surfaces with a nanometer resolution. No-slip boundary conditions are found for both fluids on hydrophilic surfaces only. Significant slip is found on the hydrophobic surfaces, with a typical length of one hundred nanometers.

PACS
47.15.Gf - Low-Reynolds-number (creeping) flows.
68.35.-p - Solid surfaces and solid-solid interfaces: Structure and energetics.

© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2002