Bending to Kinetic Energy Transfer in Adhesive Peel Front Microinstability

We report an extensive experimental study of a detachment front dynamics instability, appearing at microscopic scales during the peeling of adhesive tapes. The amplitude of this instability scales with its period as $A_{\text{mss}} \propto T_{\text{mss}}^{1/3}$, with a pre-factor evolving slightly with the peel angle $\theta$, and increasing systematically with the bending modulus $B$ of the tape backing. Establishing a local energy budget of the detachment process during one period of this micro-instability, our theoretical model shows that the elastic bending energy stored in the portion of tape to be peeled is converted into kinetic energy, providing a quantitative description of the experimental scaling law.