Séminaire de Mécanique d'Orsay
Jeudi 24 mars à 14h au FAST
Debonding mechanisms of soft adhesives: the role of viscoelasticity
Anke Lindner
PMMH, ESPCI
 

Résumé détaillé
Efficiently bonding a viscoelastic material to a rough surface is an important problem in everyday life and many industrial applications. The debonding of soft elastic materials from rough surfaces has been intensely studied and the main mechanisms are now well understood. The role of viscoelasticity is however less well understood. Here we address this question by studying the adhesion of viscoelastic model materials on surfaces with controlled periodic roughness. Figure 1: 3D visualization of the debonding of materials of different viscoelasticity. Left: debonding in the bulk of the material. Right: debonding at the interface between the material and the rigid substrate. In a first step we characterize the respective influence of elastic and viscous properties on the debonding mechanisms using homogeneous adhesive layers of a model system, allowing to go from a purely liquid material, to a viscoleastic material and finally to a soft elastic solid within one material family [1]. A new 3D visualization technique allows us to characterize the exact boundary condition between the adhesive and the solid substrate during debonding (figure 1) [2]. Fig 2 : Asymmetric profiles of our wrinkled periodic samples We then study these materials on surfaces with periodic roughness (figure 2). Depending on the material properties an increase or a decrease of the adhesion energy can be observed. The detailed results show that the macroscopic adhesion energy depends on a fine balance between the elastic energy released by the adhesive upon decompression and the viscous dissipation near the contact line during adhesive detachment.
[1] J. Nase, A. Lindner and C. Creton, Pattern formation during deformation of a confined viscoelastic layer:From a viscous liquid to a soft elastic solid, Phys. Rev. Lett. 101, (2008), 074503
[2] J. Nase, O. Ramos, C. Creton, L. Sonneberg, T. Yamaguchi and A. Lindner, A Measurement of the contact angle at the interface between a viscoelastic material and a rigid surface, Soft Matter, (2010 DOI: 10.1039/c001687j)
Résumé détaillé