Bioinspired Strategy for Controlling Crack Network Morphology on Curved Films

Fragmentation of films is not only a widely observed failure mode in engineering but can also be harnessed to modulate the performance of functional devices such as flexible sensors, nanofluidic channels, and lithographic templates. Both the sizes and geometry of fragments may influence the performance of these devices. However, existing strategies are limited to overall adjustments of fragment sizes and geometry in net‐like fragmentation across the entire films, while programming these characteristics in localized areas remains a challenge. Inspired by cracking patterns observed in animal skins, a curvature‐mediated strategy is proposed to regulate the crack network morphology on curved films. Peridynamic simulations and experiments reveal that cracks hierarchically form in thin films as substrate expansion increases, a process explained by a hierarchical shear‐lag model. Furthermore, a unified scaling law demonstrates that increasing curvature radius reduces the fragment size while increasing the number of fragment edges. This bionic strategy offers a promising method to regulate conductive pathways in thin films, providing a potential approach for the fabrication of programmable functional electronic devices.