Sensitivity and detection range-tailored self-powered sensing enabled by gradient porous nanocomposites for posture monitoring

With the self-powered capability, triboelectric sensors have shown great potential for continuous health monitoring and chronic disease prevention. Porous elastomers provide an efficient strategy to improve the flexibility and output performance of triboelectric sensors. However, increasing the flexibility usually makes a compromise in the response range. Herein, a triboelectric sensor based on gradient-pore conductive silicone rubber (G-CS) nanocomposite is fabricated, which provides high sensitivity and a wide detection range. Based on three layers of hierarchical pores, G-CS triboelectric sensor exhibits excellent flexibility (a compressive strain of 70 % per layer), a wide detection range (1.06 kPa ∼ 83.88 kPa), and high sensitivity (0.149 kPa⁻¹). Additionally, the self-foaming strategy combined with layer-by-layer casting and curing simplifies the fabrication process. The carbon nanotubes are introduced in the matrix, which provides conductivity while preserving the inherent flexibility. The gradient structure enables G-CS triboelectric sensor to detect both subtle and substantial pressure of human movement. The single G-CS sensor can be utilized to monitor sports, including foot movement and joint flexion. Moreover, G-CS sensors can be integrated into array-based smart cushions to detect the sitting state. The research shows the great potential to prevent sports injuries and improper posture, paving the way for self-powered smart healthcare.