Highly stretchable and mechanically robust silver nanowires on surface-functionalized wavy elastomers for wearable healthcare electronics

Wearable sensors have attracted significant attention for personal healthcare and human motion monitoring in recent years. In this study, a stretchable and robust stretchable sensor was fabricated by depositing silver nanowires (AgNWs) on interface-functionalized wavy polydimethylsiloxane (PDMS) substrates using an all-solution process. The interfacial adhesion between the AgNWs and stretchable substrates was significantly improved by introducing a surface modifier, ethanolamine. Stretchable films with a planar structure exhibited a small change in the resistance (5.9-fold) under 50% strain owing to the surface modification effect. The resistance of the interface-functionalized wavy film pre-strained to 125% did not change even at 170% strain. The optimized films exhibited a very small increase in resistance and improved chemical stability under repeated bending and stretch–release cycles. Sensing devices based on the interface-functionalized wavy film were realized for real-time detection of human bio-signals. With excellent sensitivity, the highly stretchable and skin-conformal sensors could successfully detect human motions and subtle bio-signals, such as facial muscle changes and breathing. In addition, the sensors reveal exceptionally low-power consumption and fast response time due to the high conductivity of the films. The high-performance stretchable, skin-compliant, interface-functionalized wavy films developed in this study have great prospects for next-generation wearable healthcare electronics.