Boundary slip on smooth hydrophobic surfaces: intrinsic effects and possible artifacts.

We report an accurate determination of the hydrodynamic boundary condition of simple liquids flowing on smooth hydrophobic surfaces using a dynamic surface force apparatus equipped with two independent subnanometer resolution sensors. The boundary slip observed is well defined and does not depend on the scale of investigation from one to several hundreds of nanometers, nor on shear rate up to 5 x 10(3)s(-1). The slip length of 20 nm is in good agreement with theory and numerical simulations concerning smooth nonwetting surfaces. These results disagree with previous data in the literature reporting very high boundary slip on similar systems. We discuss possible origins of large slip length on smooth hydrophobic surfaces due to their contamination by hydrophobic particles.

[1]  U. Raviv,et al.  Fluidity of water confined down to subnanometer films. , 2004, Langmuir : the ACS journal of surfaces and colloids.

[2]  C. Meinhart,et al.  A generating mechanism for apparent fluid slip in hydrophobic microchannels , 2004 .

[3]  J. Israelachvili,et al.  Preparing contamination-free mica substrates for surface characterization, force measurements, and imaging. , 2004, Langmuir : the ACS journal of surfaces and colloids.

[4]  Frieder Mugele,et al.  Nanofluidics: viscous dissipation in layered liquid films. , 2003, Physical review letters.

[5]  K. Breuer,et al.  APPARENT SLIP FLOWS IN HYDROPHILIC AND HYDROPHOBIC MICROCHANNELS , 2003 .

[6]  Zhiqun Lin,et al.  Platinum Nanoparticles at Mica Surfaces , 2003 .

[7]  J. Rädler,et al.  Flow profile near a wall measured by double-focus fluorescence cross-correlation. , 2003, Physical review. E, Statistical, nonlinear, and soft matter physics.

[8]  Hans-Jürgen Butt,et al.  Surface roughness and hydrodynamic boundary slip of a newtonian fluid in a completely wetting system. , 2003, Physical review letters.

[9]  J. Barrat,et al.  Low-friction flows of liquid at nanopatterned interfaces , 2003, Nature materials.

[10]  Olga I. Vinogradova,et al.  Dynamic effects on force measurements. 2. Lubrication and the atomic force microscope , 2003 .

[11]  M. Brenner,et al.  Dynamic mechanisms for apparent slip on hydrophobic surfaces. , 2003, Physical review. E, Statistical, nonlinear, and soft matter physics.

[12]  Volker Franz,et al.  Confined liquid: Simultaneous observation of a molecularly layered structure and hydrodynamic slip , 2002 .

[13]  David Quéré,et al.  Surface chemistry: Fakir droplets. , 2002, Nature materials.

[14]  J. Baudry,et al.  Nanorheology: An investigation of the boundary condition at hydrophobic and hydrophilic interfaces , 2002, The European physical journal. E, Soft matter.

[15]  J. Crassous,et al.  A new surface forces apparatus for nanorheology , 2002 .

[16]  S. Granick,et al.  Limits of the hydrodynamic no-slip boundary condition. , 2002, Physical review letters.

[17]  C. Meinhart,et al.  Apparent fluid slip at hydrophobic microchannel walls , 2002 .

[18]  P. Gennes.  On Fluid/Wall Slippage , 2001, cond-mat/0112383.

[19]  Uri Raviv,et al.  Fluidity of water confined to subnanometre films , 2001, Nature.

[20]  S. Granick,et al.  Rate-dependent slip of Newtonian liquid at smooth surfaces. , 2001, Physical review letters.

[21]  H. Christenson,et al.  Direct Measurements of the Force between Hydrophobic Surfaces in Water , 2001 .

[22]  J. Baudry,et al.  Experimental Evidence for a Large Slip Effect at a Nonwetting Fluid−Solid Interface , 2001 .

[23]  D. Williams,et al.  Shear-dependent boundary slip in an aqueous Newtonian liquid. , 2001, Physical review letters.

[24]  L. Léger,et al.  Direct experimental evidence of slip in hexadecane: solid interfaces , 2000, Physical review letters.

[25]  Lydéric Bocquet,et al.  Large Slip Effect at a Nonwetting Fluid-Solid Interface , 1999 .

[26]  S. Troian,et al.  A general boundary condition for liquid flow at solid surfaces , 1997, Nature.

[27]  Olga I. Vinogradova,et al.  Drainage of a Thin Liquid Film Confined between Hydrophobic Surfaces , 1995 .

[28]  L. Bocquet,et al.  Hydrodynamic boundary conditions, correlation functions, and Kubo relations for confined fluids. , 1994, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics.

[29]  J. Georges,et al.  Drainage of thin liquid films between relatively smooth surfaces , 1993 .

[30]  Robbins,et al.  Shear flow near solids: Epitaxial order and flow boundary conditions. , 1990, Physical review. A, Atomic, molecular, and optical physics.

[31]  Jacob N. Israelachvili,et al.  Measurement of the viscosity of liquids in very thin films , 1986 .

[32]  S. Richardson,et al.  On the no-slip boundary condition , 1973, Journal of Fluid Mechanics.

[33]  Derek Y. C. Chan,et al.  The drainage of thin liquid films between solid surfaces , 1985 .