Stretchable Multifunctional Polydimethylsiloxane Composites with Cage-Like Conductive Architecture for Integrated Thermosensitive and Electromagnetic Interference Shielding Performance

High-performance sensors with outstanding sensitivity, wide working range, and multifunctional properties are highly desirable in modern integrated smart wearable electronics. Herein, polydimethylsiloxane (PDMS)-based stretchable pyroresistive sensors composed of tightly-assembled silver nanowires (Ag NWs)-encapsulated PDMS microspheres (PM) and expandable microspheres (EM) are fabricated. The synergistic cage-like conductive network and EM endow the temperature sensor with tunable sensitivity (Max TCR: 27.4% degrees C-1), broad sensing range (25-85 degrees C), low perception limit (0.1 degrees C), and excellent anti-interference ability. Interestingly, at elevated temperature field (> 90 degrees C), a remarkable conduction-insulation transition is observed, which is employed to facilitate an early fire alarm system. In addition, the selectively distributed Ag NWs constructs segregated conductive pathways at an ultralow content (Pc = 0.014 vol%), leading to efficient electromagnetic interference shielding (40.0 dB). The underlying mechanism responsible for the observed superior thermosensation and EMI shielding performance is elucidated, and possible applications are demonstrated. Consequently, this work offers a novel strategy for the design of flexible, multifunctional pyroresistive sensors toward artificial intelligence and emerging wearable electronics.