PHYSICAL MATHEMATICS SEMINAR TOPIC: DOES STRETCHING AFFECT ADHESION? SPEAKER: CYPRIEN GAY Laboratoire CNRS France ABSTRACT: When you touch a stretched piece of rubber, it seems harder than if it is unstretched: it is less deformable. Correlatively, the adhesion between a solid and a stretched elastic material is known to be reduced as compared to the unstretched situation. But does this effect quantitatively account for the observed adhesion reduction? Considering simple geometries, we show that computing the elastic deformation by use of the Lagrangian coordinates explains experimental results obtained on stretched rubbers, without any need for altering the surface energy. In other words, we show that in such systems, adhesion at a molecular scale (i.e., surface energies) is not affected by stretching, although adhesion at a macroscopic scale is changed due to the elastic response of the material. DATE: TUESDAY, FEBRUARY 29, 2000 TIME: 2:30 PM LOCATION: Building 2, Room 338 Refreshments will be served at 3:30 PM in Room 2-349. Massachusetts Institute of Technology Department of Mathematics Cambridge, MA 02139