Unexpected frictional behavior of laser-textured hydrophobic surfaces

Hiba Jendoubi (1) , Olga Smerdova (2) , Noël Brunetière (1)

1 TriboLub - Mécanique des interfaces lubrifiées [Institut Pprime]
2 ENDO - ENDOmmagement et durabilité [Institut Pprime]

Hydrophobic surfaces can allow a liquid to slip over the surface and can thus reduce 1 friction in lubricated contact working in a full film regime. Theory supports that the amount of slip 2 can be increased if super-hydrophobic surfaces that are composed of a textured low surface energy 3 material are used. In this work, polytetrafluoroethylene (PTFE) polymer samples were textured 4 with a femto second laser to create super-hydrophobic surfaces by machining a hexagonal network 5 of small circular holes with 10 and 20 µm lattice sides. The frictional behavior of these surfaces 6 was compared to the smooth PTFE samples. Surprisingly, the textured surfaces revealed higher 7 friction coefficients than the smooth surfaces. This higher friction can be explained by a change of 8 wetting regime due to high pressure in fluid and a possible generation of vortices in the cavities.

Mots clés: Surface texture; Hydrophobic surface; Friction; Lubrication

Domaines: Mécanique [physics.med-ph]

Hiba Jendoubi, Olga Smerdova, Noël Brunetière. Unexpected frictional behavior of laser-textured hydrophobic surfaces. Lubricants, 2021, 9 (3), pp.31. ⟨10.3390/lubricants9030031⟩. ⟨hal-03376141⟩