Abstract
Wearable electronics hold great promise for health management and chronic disease monitoring, yet their widespread applications are limited by insufficient stretchability, breathability, and mechano-electrical stability. Herein, we report a swelling-induced modulus design that enables the construction of breathable and strain-isolated substrates for integrated electronics. The swelling-induced in-situ polymerization of acrylates within polyurethane membrane effectively enhances the mechanical properties while preserving air permeability. In addition, by optimizing substrate modulus and interfacial contact, rigid islands for supporting functional devices and soft bridges for assembling interconnects are rationally designed. As a result, the circuit board achieves high stretchability (519%, 3.86 MPa) and electrical stability (ΔR/R0 = 3.78 under 500% strain), together with high air (31.4 mm s-1) and moisture (2577.67 g m-2 day-1) permeability, outperforming previously reported stretchable and breathable supports. A stretchable and breathable system is also demonstrated, which integrates wireless charging, energy storage, and sensing for posture monitoring with long-term comfortable wear.