Formation of adhesive contacts: spreading versus dewetting.
A soft bead (radius Rb) is pressed with a force F against a hydrophobic glass plate through a water drop ("wet" JKR set-up). We observe with a fast camera the growth of the contact zone bridging the rubber bead to the glass. Depending on the approach velocity V, two regimes are observed: i) at large V a liquid film is squeezed at the interface and dewets by nucleation and growth of a dry contact; ii) at low velocities, the bead remains nearly spherical. As it comes into contact, the rubber bead spreads on the glass with a characteristic time (in the range of one millisecond) tau approximately eta Rb2/F, where eta is the liquid viscosity. The laws of spreading are interpreted by a balance of global mechanical and viscous forces.
Verneuil
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E
Laboratoire Physico-Chimie Curie, UMR 168-Institut Curie, 11, rue Pierre et Marie Curie 75231 Paris Cedex 05, France.
Clain
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J
Buguin
A
A
Brochard-Wyart
F
F
D003198:Computer Simulation; D004548:Elasticity; D004735:Energy Transfer; D017276:Friction; D008846:Micromanipulation; D008956:Models, Chemical; D009038:Motion; D010316:Particle Size; D015203:Reproducibility of Results; D012408:Rubber / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013500:Surface Tension; D000267:Tissue Adhesions; D014783:Viscosity; D014867:Water / Q000737:chemistry*; D017155:Wettability
D014867:Water; D012408:Rubber