Highly Sensitive and Low Detection Limit Flexible Pressure Sensor Based on Modified TiO2 Cocooned Elastic Sponge for Wearable Applications

Pressure sensors with excellent performance have widely attracted extensive interest in developing flexible sensors. Polyurethane (PU) sponge has attracted wide attention owing to their porous structure, excellent mechanical flexibility, and elasticity. Herein, we reported an efficient strategy to enhance the performance of the capacitive pressure sensor by fabricating a cocooned PU elastic sponge consisting of TiO2 nanoparticles modified with 3-aminopropyltriethoxysilane (APTES). The tactile perception mechanism and sensing properties of the developed devices were investigated. In addition, the TiO2@PU sponge prepared with 1 mg/mL nano-TiO2 aqueous solution enhanced interfacial polarization exhibiting a significantly improved dielectric property. The capacitive sensor exhibited superb electromechanical properties such as an ultrahigh sensitivity of 0.93 kPa $^{-{1}}$ , a low detection limit of 1.4 Pa, and stability over 1000 cycles. This flexible sensor can be used as a wearable electronic skin mounted on the human body for real-time indicator monitoring. High sensitivity and low detection limit make the sensor a potential candidate for multifunctional sensing platforms such as wearable electronic devices, flexible displays, smart mobile systems, and more.