Wide-range human physiological signal acquisition with carbonized composite nanofibers

Flexible pressure sensors provide a powerful platform for information acquisition from the surrounding environment and individual body with bendable, stretchable, conformal and biocompatible properties. However, current pressure sensors with high sensitivity often come at a high cost and have a limited pressure measurement range, which remarkably constrains their adaptability to the diverse physiological activities. Herein, we developed carbonized polyacrylonitrile (PAN) nanofibers (CPNs) by combining electrospinning with high-temperature carbonization. The synthesized CPNs feature low production costs, excellent stress transmission properties, and controllable electrical conductivity and morphologies, achieving substantial merits of flexible pressure detection. The dependence of pressure sensing performance on carbonization temperature, mass ratio of composite materials, film thickness, and surface microstructure design was systematically investigated. CPN/BC-based flexible pressure sensors (CFPSs) demonstrate an ultra-wide operating range from 0 to 250 kPa, high sensitivity (19.20 [kPa]^-1), and rapid response and recovery times (62/32 ms). The as-fabricated CFPS can effectively monitor physiological signals across various pressure ranges, realizing a variety of practical applications like intelligent healthcare, human-computer interaction, and the Internet of Things (IoT).