title: Molecular Weight Dependence of Interdiffusion and Adhesion of Polymers at Short Contact Times.
abstract: The autohesion and subsequent debonding of thin layers of three linear and monodisperse random copolymers of styrene-butadiene (SBR) with molecular weights varying between 30 and 75 times the average molecular weight between entanglements Mewere investigated using a carefully controlled tack adhesion testing device in conjunction with a fast camera setup over a range of contact times tc(10 ms to 10 s) much shorter in comparison to the terminal relaxation times of the polymers. The evolution of the stress-strain curves and debonding mechanisms with increasing contact time was examined, and the work required to debond the layers was found to be strongly dependent on molecular weight at long contact times, but not at short contact times. We propose a cutoff contact time of 300 ms, corresponding to 104times the entanglement time τeafter which molecular weight becomes important in controlling the interdiffusion process and the debonding mechanisms of the tack test. For contact times over 300 ms, the debonding energy plotted as a function of tcnormalized by the reptation time τrep, collapses onto a master curve. Below this threshold tc, by comparing the adhesion of SBR on itself with the adhesion of SBR on glass, we also show that interdiffusion plays a part in adhesion of two identical polymer layers even at the shortest contact times, where the interdiffusion is controlled by the number of entanglements formed which scales with 1/√N.
authors.affiliation: Laboratoire de Sciences et Ingénierie de la Matière Molle, CNRS, ESPCI Paris, PSL Research University , 10 Rue Vauquelin, 75005 Paris, France.|Laboratoire de Physique et Mécanique des Milieux Hétérogènes, CNRS, ESPCI Paris, PSL Research University, University Pierre et Marie Curie, University Paris Diderot , 10 Rue Vauquelin, 75005 Paris, France.
authors.forename: Robert
authors.initials: R
authors.lastname: Gurney
authors.affiliation: Centre de Technologies Michelin , 63118 Ladoux, France.
authors.forename: Anastase
authors.initials: A
authors.lastname: Henry
authors.affiliation: Centre de Technologies Michelin , 63118 Ladoux, France.
authors.forename: Regis
authors.initials: R
authors.lastname: Schach
authors.affiliation: Global Station for Soft Matter, Global Institution for Collaborative Research and Education, Hokkaido University , Sapporo 060-0808, Japan.|Laboratoire de Physique et Mécanique des Milieux Hétérogènes, CNRS, ESPCI Paris, PSL Research University, University Pierre et Marie Curie, University Paris Diderot , 10 Rue Vauquelin, 75005 Paris, France.
authors.forename: Anke
authors.initials: A
authors.lastname: Lindner
authors.affiliation: Laboratoire de Sciences et Ingénierie de la Matière Molle, CNRS, ESPCI Paris, PSL Research University , 10 Rue Vauquelin, 75005 Paris, France.|Global Station for Soft Matter, Global Institution for Collaborative Research and Education, Hokkaido University , Sapporo 060-0808, Japan.
authors.forename: Costantino
authors.identifier: 0000-0002-0177-9680
authors.initials: C
authors.lastname: Creton