High-stability flexible body motion monitoring sensor based on waterborne polyurethane-coated conductive warp-knitted fabric

To prepare a high-stability flexible sensor for body motion monitoring, a conductive warp-knitted fabric (CWKF) with a two-bar tricot structure coated with polyaniline(PANI) was prepared by in situ polymerization, and then a waterborne polyurethane-coated conductive warp-knitted fabric (WPU/CWKF) was prepared using a simple dip-and-dry method. The structure and properties of both CWKF and WPU/CWKF were analyzed, their strain-resistance sensing properties were investigated, and their application in body motion monitoring was discussed. The results indicate that conductive treatment of in situ polymerization can give the polyester warp-knitted fabric good electrical conductivity, with a resistivity of approximately 5 Ω cm. After coating with WPU, the resistivity of the WPU/CKWF increased to approximately 40 Ω cm. Both CKWF and WPU/CKWF showed good strain-resistance sensing performance, but CWKF was more sensitive than WPU/CKWF, whereas WPU/CKWF was more stable than CWKF. Both the CWKF and WPU/CKWF sensors could monitor body motion in real time. Similar to their base materials, the CWKF sensor demonstrated a higher sensitivity for human movement monitoring, whereas the WPU/CKWF sensor exhibited higher stability. Conductive warp-knitted fabric (CWKF) with a two-bar tricot warp-knitted structure coated with polyaniline (PANI) was prepared by in situ polymerisation. After repeated reciprocal stretching, the structure of the PANI conductive layer on the CWKF surface broke down and its conductivity changed, especially under large strains. CWKF sensors enable real-time human motion monitoring with high sensitivity