Flexible Piezoresistive Sensor With High Strain Sensitivity and Pressure Insensitivity for Motion Monitoring

Flexible strain sensors have attracted particular attention in monitoring the biological activity of organisms. This article presents a flexible piezoresistive strain sensor (FPSS) that uses nano- and micromaterials and a sensitive unit with a microspheric structure. The stretchable strain sensor exploits carbon nanotubes (CNTs) and achieves stable strain sensing performance with excellent Qhmic characteristics and good durability, possesses a high sensitivity [gauge factor (GF) ≈ 146] under tensile strain, and is insensitive to pressure. While attached to human skin areas, it can distinguish facial expressions, deep breathing, and finger motions. These results imply this strain sensor may have applications in e-skins.