A Versatile Microporous Design toward Toughened yet Softened Self-Healing Materials.

Realizing the full potential of self-healing materials in stretchable electronics necessitates not only low modulus to enable high adaptivity, but also high toughness to resist crack propagation. However, existing toughening strategies for soft self-healing materials have only modestly improves mechanical dissipation near the crack tip (Г), and invariably compromise the material's inherent softness and autonomous healing capabilities. Here, a synthetic microporous architecture is demonstrated that unprecedently toughens and softens self-healing materials without impacting their intrinsic self-healing kinetics. This microporous structure spreads energy dissipation across the entire material through a bran-new dissipative mode of adaptable crack movement (Г), which substantially increases the fracture toughness by 31.6 times, from 3.19 to 100.86 kJ m, and the fractocohesive length by 20.7 times, from 0.59 mm to 12.24 mm. This combination of unprecedented fracture toughness (100.86 kJ m) and centimeter-scale fractocohesive length (1.23 cm) surpasses all previous records for synthetic soft self-healing materials and even exceeds those of light alloys. Coupled with significantly enhanced softness (0.43 MPa) and nearly perfect autonomous self-healing efficiency (≈100%), this robust material is ideal for constructing durable kirigami electronics for wearable devices.