Versatile Electronic Skins for Motion Detection of Joints Enabled by Aligned Few‐Walled Carbon Nanotubes in Flexible Polymer Composites

Here, novel multifunctional electronic skins (E‐skins) based on aligned few‐walled carbon nanotube (AFWCNT) polymer composites with a piezoresistive functioning mechanism different from the mostly investigated theory of “tunneling current channels” in randomly dispersed CNT polymer composites are demonstrated. The high performances of as‐prepared E‐skins originate from the anisotropic conductivity of AFWCNT array embedded in flexible composite and the distinct variation of “tube‐to‐tube” interfacial resistance responsive to bending or stretching. The polymer/AFWCNT‐based flexion‐sensitive E‐skins exhibit high precision and linearity, together with low power consumption (<10 µW) and good stability (no degradation after 15 000 bending–unbending cycles). Moreover, polymer/AFWCNT composites can also be used for the construction of tensile‐sensitive E‐skins, which exhibit high sensitivity toward tensile force. The polymer/AFWCNT‐based E‐skins show remarkable performances when applied to monitor the motions and postures of body joints (such as fingers), a capability that can find wide applications in wearable human–machine communication interfaces, portable motion detectors, and bionic robots.