High-performance polyacrylic acid/ carboxylated cellulose nanofibers hydrogel sensor for human-machine interaction

Ion-conductive hydrogels have emerged as the promising candidate materials for flexible sensors due to their high ion migration efficiency and rapid responsiveness. However, achieving synergistic optimization of the mechanical, electrical and sensing properties of ion-conductive hydrogels remains a challenge. This study synthesized a dual-network ion-conductive hydrogel (PCN) via an in-situ thermal radical polymerization method. This hydrogel is formed through multiple cross-linking mechanisms involving covalent bonds, ionic bonds and hydrogen bonds. The optimal hydrogel (PCN-30) exhibits outstanding mechanical properties across a broad strain and temperature range (938 % tensile strain, 0.23 MPa tensile strength) and sensing performance (its relative resistance change exhibits good linearity with both tensile strain and temperature variation. For tensile strains of 10-300 %, the average gauge factor (GF¯) reaches 1.71. During temperature rise (15-45 °C) and drop (-35-15 °C) processes, GF¯ are 2.46 and 1.63, respectively). Additionally, PCN-30 as a sensor enables rapid and precise motion and vital sign sensing as well as information transmission. This work highlights that the hydrogel combines the environmental adaptability over a wide temperature range and the sensitive response capability within a wide strain range, greatly promoting its practical application in the field of human-computer interaction.