Patterned Carbon Nanotube Bundles as Stretchable Strain\nSensors for Human Motion Detection

Abstract

Although\nnumerous studies have been conducted to develop wearable\nstrain sensors with high sensitivity and a wide detection range, developing\nstrain sensors with tunable sensitivity for practical purposes remains\nchallenging. Strain sensors with tunable sensitivity have great potential\nin applications such as human motion detection and health monitoring.\nThis paper introduces strain sensors that adopt zigzag-patterned carbon\nnanotube (CNT) bundle arrays embedded in a polymer matrix. Owing to\nthe zigzag pattern, the sensors exhibited an extensive detection range\nup to 500% strain and high sensitivity (gauge factor of 64.08). In\nthis study, the CNT bundle array synthesized on a Si wafer was transferred\nto a silicone elastomer substrate using a roll-transfer technique,\nforming a sheet-like structure of overlapped CNT bundles. The separation\noccurring between the CNT bundles with the applied strain followed\nthe shape of the zigzag pattern. The sensors exhibited excellent repeatability\nand durability with negligible hysteresis behavior, and their sensitivity\nwas tunable based on the pattern design. Furthermore, this study investigated\nthe sensing mechanism of the sensors and their potential use in wearable\nelectronics.