Ultrasensitive Mg²⁺-Modulated Carbon Nanotube/Tannic Acid Aerogels for High-Performance Wearable Pressure Sensors

Abstract

Three-dimensional (3D) carbon nanotube-based porous networks have received considerable attention as active nanomaterials for flexible/wearable sensor applications due to their excellent conductivity and mechanical flexibility. Herein, ultralight, biocompatible, and conductive SWCNT/tannic acid (TA) and Mg2+/SWCNT/TA aerogels have been facilely fabricated using TA as a dispersion reagent and crosslinker and Mg2+ to introduce a metal–phenolic network. The construction of a SWCNT@TA core–shell structure and the low CNT concentration of SWCNT/TA3:3 contribute to a high linear sensitivity of 432 kPa–1 in a wide pressure range (0.014–28 kPa), while Mg2+ modulation endows Mg2+/SWCNT/TA1:1 with an ultrahigh linear sensitivity of 13662 kPa–1 in a pressure range of 0.014–1.05 kPa. The superior sensing performance of as-prepared aerogels, including high sensitivity, wide working range, low detection limit (14 Pa), and fast stimuli-response (200–300 ms), enables them to detect tiny changes in human biosignals and imperceptible vibration, which show great potential in applications of health monitoring, human–machine interfaces, and various flexible electronics