Multilayer nanofiber yarns via electrospinning-assisted continuous fabrication for body motion monitoring and intelligent rehabilitation

Core spun/sheath yarns for textile-based triboelectric nanogenerators (T-TENGs) have garnered significant interest in the field of flexible wearables owing to their unique multilayer structure. However, poor interfacial compatibility and insufficient mechanical durability between yarn structures lead to charge leakage and unstable performance output in triboelectric nanogenerators. In this study, we have designed and achieved the continuous fabrication of highly uniform, super-durable, and ultrafine multilayer nanofiber yarns (MNY) through a simple electrospinning-assisted and coating technique. By optimizing the electrospinning process, nanoscale fibers were used to tightly and uniformly form the multilayer structure without compromising charge transfer between the conductive and triboelectric layers. Additionally, the multilayer triboelectric nanogenerators (MNY-TENG) demonstrated stable and consistent electrical responses in terms of output voltage and short-circuit current under varying loads and frequencies, maintaining stable voltage output over 30,000 contact cycles and 20 washing cycles. Furthermore, the MNY-TENG shows great potential in various life scenarios, including monitoring body signals and badminton stroke posture, and has been innovatively combined with machine learning for upper limb rehabilitation training.