3D interlocked all-textile structured triboelectric pressure sensor for accurately measuring epidermal pulse waves in amphibious environments

The performance degradation and even damage of the e-textiles caused by sweat, water, or submersion during all-weather health monitoring are the main reasons that e-textiles have not been commercialized and routinized so far. Herein, we developed an amphibious, high-performance, air-permeable, and comfortable all-textile triboelectric sensor for continuous and precise measurement of epidermal pulse waves during full-day activities. Based on the principle of preparing gas by acid-base neutralization reaction, a one-piece preparation process of amphibious conductive yarn (ACY) with densely porous structures is proposed. An innovative three-dimensional (3D) interlocking fabric knitted from ACYs (0.6 mm in diameter) and polytetrafluoroethylene yarns exhibit high sensitivity (0.433 V·kPa−1), wide bandwidth (up to 10 Hz), and stability (> 30,000 cycles). With these benefits, 98.8% agreement was achieved between wrist pulse waves acquired by the sensor and a high-precision laser vibrometer. Furthermore, the polytetrafluoroethylene yarn with good compression resilience provides sufficient mechanical support for the contact separation of the ACYs. Meanwhile, the unique skeletonized design of the 3D interlocking structure can effectively relieve the water pressure on the sensor surface to obtain stable and accurate pulse waves (underwater depth of 5 cm). This achievement represents an important step in improving the practicality of e-textiles and early diagnosis of cardiovascular diseases.