Pull-Off of adhesive viscoelastic solids

Work package:
Solid viscoelastic materials are commonly used for adhesion (ex: adhesive tape, reversible sealing for microfluidic [1, 2], etc.). They exhibit simultaneous viscous and elastic characteristics. In the case of solid-viscoelastic rubbers, their solid behavior is a consequence of their crosslinked polymer network which can elastically recover once an applied force is stopped. Furthermore, its liquid behavior is due to a flow between macromolecules and give a viscosity dependent flow rate when stress is applied. It adds a time dependent trend on the stress-strain relationship. If a viscoelastic adhesive material is tearing very fast, it acts as a solid. On the other hand, for low pulling rate, all the viscous components are relaxed. Between those two domains, the response is a combination of the viscous and elastic behaviors. This velocity dependence is not experimentally studied in the literature [3, 4] which results in non-comparable and partial measurements. Exploring the pull-off dynamics of adhesion with a wide range of pulling rates will lead to a new methodology for viscoelastic adhesion measurements. The results obtained in this study will be compared with theoretical models [5] to get an experiment/model convergence. The experiment will be: Casting viscoelastic samples Create and modify measuring program (Labview or python) Measure pull-off forces Adapt the set-up to go near the theorical model Mechanical properties and shape of the adhesive sample Size of the indenter to stay in the working range of the machine