An electrically conductive polyvinyl alcohol/poly (acrylic acid-co-acrylamide)/polydopamine-decorated carbon nanotubes composite hydrogel with appropriate mechanical properties for human movement monitoring

In recent years, flexible wearable electronic devices have received extensive attention in the fields of human health monitoring, bioelectronic interfaces, and human–computer interaction. Conductive hydrogels have gradually become the best candidate materials for flexible wearable electronic devices, due to their good conductive properties, elastic modulus similar to natural skin tissue, and adjustable mechanical properties. In this study, polyvinyl alcohol/poly (acrylic acid-co-acrylamide)/polydopamine-decorated carbon nanotubes (PVA/P(AA-co-AM)/PDA@CNTs) composite hydrogel was prepared by free radical copolymerization and in situ composite methods. The double-physical cross-linked network composed of PVA and P(AA-co-AM) formed an efficient energy dissipation system. The composite hydrogel exhibits appropriate mechanical properties (tensile strength of 1.21 ± 0.04 MPa, elongation at break of 221.28 ± 2.04%, toughness of 1.22 ± 0.36 MJ m⁻³). PDA@CNTs formed conductive pathways in the composite hydrogel, which endowed hydrogel with electrical conductivity (3.84 S/m) and high sensitivity (gauge factor of 1.6). The wearable sensor based on composite hydrogel can monitor the joint movement and muscle movement of the human body. PVA/P(AA-co-AM)/PDA@CNTs composite hydrogel has great application prospects in the field of flexible wearable electronic devices for human movement monitoring.