Bioinspired Asymmetric Porous Natural Rubber Films: Wearables for Electromagnetic Shielding, Fetal Monitoring, and Personal Thermal Management

Abstract Materials that integrate flexibility, electromagnetic shielding, and Joule heating are crucial for the development of multifunctional wearable technologies. Inspired by the trabecular structure, this study used natural rubber as a matrix and added sodium alginate‐modified carbon nanotubes. A multifunctional composite (SCN) with a bone trabecular‐like asymmetric porous structure is prepared via dynamic crosslinking and a synergistic microphase separation‐induced effect. The asymmetric porous SCN exhibited exceptional tensile properties (7.75 MPa tensile strength, 445% elongation at break), excellent low‐strain sensing performance (gauge factor (GF) up to 3.46 at 1–10% strain), rapid Joule heating (63.2% thermal saturation in <9 s), and effective electromagnetic interference (EMI) shielding (22.7 dB in the X‐band for a 109‐µm film). Machine learning achieved 95.56% accuracy in differentiating fetal‐movement frequencies, indicating the potential of SCN for fetal health monitoring. An SCN‐based thermal management system developed by a microcontroller unit (MCU) rapidly heated the film surface temperature to 35.4 °C within 30 s at 3 V. Furthermore, SCN composites exhibited antibacterial efficacy against Staphylococcus aureus (99.70% inhibition) and Escherichia coli (99.30% inhibition). These properties make the multifunctional asymmetric porous SCN a promising material for next‐generation wearable electronics, offering EMI shielding, personal temperature management, and health monitoring.