Probing the nanohydrodynamics at liquid-solid interfaces using thermal motion

L. Joly (1) , C. Ybert (1) , L. Bocquet (1)

1 LPMCN - Laboratoire de Physique de la Matière Condensée et Nanostructures

We report on a new method to characterize nano-hydrodynamic properties at the liquid/solid interface relying solely on the measurement of the thermal motion of confined colloids. Using Fluorescence Correlation Spectroscopy (FCS) to probe the diffusion of the colloidal tracers, this optical technique --equivalent in spirit to the microrheology technique used for bulk properties-- is able to achieve nanometric resolution on the slip length measurement. It confirms the no-slip boundary condition on wetting surfaces and shows a partial slip b=18 +/- 5 nm on non-wetting ones. Moreover, in the absence of external forcing, we do not find any evidence for large nano-bubble promoted slippage on moderately rough non-wetting surfaces.

Mots clés: slip; wetting; surface roughness; hydrodynamics; liquid films

Domaines: Matière Molle [cond-mat.soft]; Mécanique statistique [cond-mat.stat-mech]

L. Joly, C. Ybert, L. Bocquet. Probing the nanohydrodynamics at liquid-solid interfaces using thermal motion. Physical Review Letters, 2006, 96 (4), pp.046101. ⟨10.1103/PhysRevLett.96.046101⟩. ⟨hal-00437085⟩