Figure 3.

(a) Scanning electron micrograph of the Tarsus of the leg of a bush cricket (reproduced with kind permission from S. Gorb (Scherge & Gorb 2000)). We are trying to mimic the adhesion originating from the discontinuities resulting from such segmentation. (b) The peeling moment, M, as a function of the plate displacement, Δ, for differently incised films made of PDMS of shear modulus 0.9 MPa and thickness 305 μm, using cover plate of rigidity D=0.05 Nm. All incisions were made to a maximum depth δ of ∼100 μm with the lateral and longitudinal spacing (s) of ∼250 μm each. Black curve: no incision, edge crack; blue curve: multiple lateral incisions; green curve: multiple longitudinal incisions; red curve: multiple crosswise incisions. (c)–(f) Sequences of the crack opening modes: (c) edge crack, (d) lateral incisions, (e) longitudinal incisions and (f) crosswise incisions. The scale bars in (c)–(f) are 2 mm. In all cases, the crack propagates from right to left.