Sensitivity-tunable flexible ion–electron synergistic pressure sensor for high-resolution occlusal force mapping

A bilayer ion–electron design harmonizes high sensitivity with rapid dynamic response. • Tunable sensitivity is achieved by tailoring MXene doping from 0.02 to 0.10 mg/mL. • 2 wt% CNT loading optimizes percolation, avoiding rigid filler agglomeration. • Robust durability is validated under saliva wetting, shear, and bionic occlusion. High-resolution, wide-range occlusal force monitoring is crucial for diagnosing temporomandibular disorders and optimizing dental prosthetics. However, current clinical tools lack sufficient flexibility, spatial resolution, and dynamic response range. This work develops a flexible, sensitivity-tunable pressure sensor tailored for quantitative full-arch occlusal force mapping. An ion–electron synergistic piezoresistive sensor was fabricated in a bilayer heterogeneous structure, integrating an ionically conductive, MXene-doped poly(AMPS-co-AA) hydrogel sensory layer with an electronically conductive carbon nanotube/thermoplastic polyurethane (CNT/TPU) transduction film. Interfacial adhesion was optimized using O₂ plasma activation, PEDOT modification, and hot-press crosslinking. This synergistic design harmonizes high sensitivity with rapid dynamic response (58 μs for the electronic layer and 3 ms for the ionic layer). The fabricated device demonstrated a wide dynamic response range up to 30 N and outstanding mechanical durability over 1000 cycles. Systematic screening revealed that a 2 wt% CNT loading forms an optimal percolation network that minimizes interfacial charge-transfer resistance, whereas a 3 wt% loading induces microscale contact loss and signal fluctuations. Evaluations using a 3D-printed bionic oral model across full-arch dental positions showed good agreement with the FEA-predicted stress gradients. This sensing platform offers a practical, high-fidelity approach for digitized occlusal force mapping and oral biomechanical assessment. Download: Download high-res image (191KB) Download: Download full-size image