Low-friction flows of liquid at nanopatterned interfaces.
With the important development of microfluidic systems, miniaturization of flow devices has become a real challenge. Microchannels, however, are characterized by a large surface-to-volume ratio, so that surface properties strongly affect flow resistance in submicrometre devices. We present here results showing that the concerted effect of wetting properties and surface roughness may considerably reduce friction of the fluid past the boundaries. The slippage of the fluid at the channel boundaries is shown to be greatly increased by using surfaces that are patterned on the nanometre scale. This effect occurs in the regime where the surface pattern is partially dewetted, in the spirit of the 'superhydrophobic' effects that have been discovered at macroscopic scales. Our results show for the first time that, in contrast to common belief, surface friction may be reduced by surface roughness. They also open the possibility of a controlled realization of the 'nanobubbles' that have long been suspected to play a role in interfacial slippage.
Cottin-Bizonne
Cécile
C
Laboratoire de Physique de la Matière Condensée et Nanostructures, CNRS and Université de Lyon, Bâtiment Léon Brillouin, 43 Boulevard du 11 Novembre, 69622 Villeurbanne Cedex, France.
Barrat
Jean-Louis
JL
Bocquet
Lydéric
L
Charlaix
Elisabeth
E
D017276:Friction; D006244:Hardness; D057927:Hydrophobic and Hydrophilic Interactions; D036103:Nanotechnology / Q000379:methods*; D011312:Pressure; D012212:Rheology / Q000379:methods*; D033081:Shear Strength; D012996:Solutions / Q000737:chemistry*; D013499:Surface Properties; D014783:Viscosity; D017155:Wettability
D012996:Solutions