PVDF/carbon directional microchannels-enhanced ion diode-like hydrogel-based pressure sensors

Hydrogels are promising candidates for flexible electronics but are often constrained by narrow pressure-sensing ranges and unstable ion migration. To overcome these limitations, we developed an ionic hydrogel sensor incorporating diode-inspired bipolar architectures (PSSNa/PDACl) and poly(vinylidene fluoride)/carbon directional microchannels (PCDMC). The optimized 5-PCNPC hydrogel exhibits a broad pressure-sensing range (2.3–100 kPa) with a sensitivity of 0.360 mV·kPa⁻¹ (a 34.8 % enhancement) and a rectification ratio of 12.9, enabled by PCDMC-guided anisotropic ion transport and rapid stress dissipation (337 ms recovery). With excellent durability over 500 cycles and a power density of 1.17 mW·m⁻², the hydrogel sensor demonstrates its potential in practical applications, including a 5 × 5 touchpad for spatial pressure mapping and real-time monitoring of respiration, swallowing, grasping and locomotion. This study underscores the potential of hydrogel-based sensors with wide-range operability for next-generation wearables and interactive systems.