Superhydrophobic Wearable Dual-Mode Sensor Based on Laser-Induced Graphene Composites and Hierarchical Sensing Mechanism

Wearable flexible sensors still face sensitivity to environmental interference, a narrow pressure detection range, and complex fabrication. Here, we propose a superhydrophobic, dual-mode sensor that combines laser-induced graphene (LIG) and a composite hydrogel through three key strategies. First, a viscous hydrogel is used to transfer LIG, preserving its porous structure (>95% porosity retention) and enhancing the piezoresistive response. Second, the same hydrogel viscosity uniformly anchors SiO 2 nanoparticles on the surface, forming a stable superhydrophobic interface with a contact angle of 151°. Third, a 3D-printed microprotrusion hydrogel layer (700 μm) is integrated with the LIG to create a hierarchical pressure-sensing mechanism, which responds independently to small pressures (1–5 N) and works synergistically for large-range detection (5–50 N) with high linearity ( R 2 = 0.992). The resulting sensor detects both pressure and stretching, with a fast response (<800 ms) and strong environmental resilience. Fabricated by a low-cost, all-physical process that reduces the unit cost by 70%, it has been successfully applied to monitor physiological signals such as finger bending, joint movement, and swallowing. This work provides an efficient solution for advanced wearable devices in medical rehabilitation and sports monitoring.