  Using a high-speed camera, we follow the propagation of the detachment front
during the peeling of an adhesive tape from a flat surface. In a given range of
peeling velocity, this front displays a multiscale unstable dynamics,
entangling two well-separated spatiotemporal scales, which correspond to
microscopic and macroscopic dynamical stick-slip instabilities. While the
periodic release of the stretch energy of the whole peeled ribbon drives the
classical macro-stick-slip, we show that the micro-stick-slip, due to the
regular propagation of transverse dynamic fractures discovered by Thoroddsen et
al. [Phys. Rev. E 82, 046107 (2010)], is related to a high-frequency periodic
release of the elastic bending energy of the adhesive ribbon concentrated in
the vicinity of the peeling front.
