Superhydrophobic MXene-CNT bridge strain sensors with wide Linear-Range via strain-isolation and crack-synergy effects

Despite the high sensitivity of crack-based strain sensors, extending their linear range remains challenging. Additionally, maintaining inherent superhydrophobicity is crucial for their effective operation in complex hydrated scenarios. In this study, we introduce a superhydrophobic MXene-CNT bridge (MCB) strain sensor that utilizes multi-structural strategies to modulate crack propagation. The MCB sensor leverages the strain isolation effect of the bridge structure to reduce excessive stress concentration from existing cracks in the substrate, leading to a more gradual redistribution of cracks in the conductive layer, thus ensuring its sensitivity and stretchability. Furthermore, the sensor capitalizes on the crack-synergy effects of the dual conductive layers to achieve a wide linear range: a MXene film for slight deformations and a superhydrophobic CNT-Ecoflex composite for significant ones. The fabricated MCB sensor showcases its ability to monitor electrophysiological signals and capture body motion, even in underwater conditions. The suggested multi-structural strategies provide a straightforward method for fabricating sensors that capture human physiological signatures in aquatic settings.