We perform traction experiments on viscous liquids highly confined betweenparallel plates, a geometry known as the probe-tack test in the adhesioncommunity. Direct observation during the experiment coupled to forcemeasurement shows the existence of several mechanisms for releasing the stress.Bubble nucleation and instantaneous growth had been observed in a previouswork. Upon increasing further the traction velocity or the viscosity, thebubble growth is progressively delayed. At high velocities, cracks at theinterface between the plate and the liquid appear before the bubbles have grownto their full size. Bubbles and cracks are thus observed concomitantly. At evenhigher velocities, cracks develop fully so early that the bubbles are not evenvisible. We present a theoretical model that describes these regimes, using aMaxwell fluid as a model for the actual fluid, a highly viscous silicon oil. Wepresent the resulting phase diagramme for the different force peak regimes. Thepredictions are compatible with the data. Our results show that in addition tocavitation, interfacial cracks are encountered in a probe-tack traction testwith viscoelastic, \emph{liquid} materials and not solely with viscoelasticsolids like adhesives.
展开▼
