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Accueil > Evénements > Séminaires > Archives 2015 > Rate-dependent elastic
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Séminaire « Matière molle : organisation et dynamique » de l’INSP

Rate-dependent elastic hysteresis during the peeling of Pressure Sensitive Adhesives - Matteo Ciccotti - Lundi 23 mars 2015 à 11 h

INSP - 4 place Jussieu - 75252 PARIS Cedex 05 - Barre 22-32 - 2e étage, salle 201

Matteo Ciccotti - Laboratoire SIMM, UPMC-CNRS-ESPCI Paritech

Abstract

The modeling of the adherence energy during peeling of Pressure Sensitive Adhesives (PSA) has received much attention since the 1950’s, uncovering several factors that aim at explaining their high adherence on most substrates, such as the softness of the adhesive, its strong viscoelastic behavior, the low thickness of the adhesive layer and its confinement by a rigid backing. The more recent investigation of adhesives by probe-tack methods also revealed the importance of cavitation and stringing mechanisms during debonding, underlining the influence of large deformations and of the related non-linear response of the material which also intervenes during peeling. Although a global modeling of the complex coupling of all these ingredients remains out of reach, we report here some key experiments and modeling arguments that should constitute an important step forward. We first measure a non-trivial dependence of the adherence energy on the loading geometry, namely through the influence of the peeling angle, which is found to be separable from the peeling velocity dependence. Secondly, we measure an independent effect of non-linear rheology on adhesives that have nearly the same linear rheology and remain close to commercial PSA. We complete both measurements with a microscopic investigation of the bonding region. We discuss existing modelings in light of these measurements and of recent soft material mechanics arguments to show that the adherence energy during peeling of PSA should not be associated to the propagation of an interfacial stress singularity, but to the energy loss by viscoelastic hysteresis associated to the deformation mechanisms over the whole adhesive thickness.