• • BIEFI achieves a maximum adhesion fracture point that extends stretchability beyond conventional rigid island methods, with primary roots delaying interfacial failure and secondary roots providing flexible interlocking until a deformation threshold, enabling reliable operation under repeated stretching and twisting.
• • Optimization of primary root number (N), secondary root number (Rn), and root width (K) shows that increasing N directly enhances stretchability, providing a tunable design parameter for matching specific strain requirements in wearable electronics.
• • The root-soil inspired interlocking mechanism suppresses interfacial failure by grasping the elastomer, allowing flexible movement under strain and maintaining adhesion up to the maximum fracture point, which is critical for long-term stability in stretchable devices.
• • A smart resistance band for workout monitoring demonstrates practical application, validating BIEFI's potential for commercial wearable systems that require robust integration of rigid components with soft substrates.