Enhanced carbon dispersion of polyacrylamide/sodium alginate hydrogels via irregular copolymerization imidazolyl ionic liquid for flexible sensor

Abstract

Electrically conductive hydrogel matrices embedded with carbon-based nanomaterials have undergone comprehensive scientific examination, showing notable promise for implementation in next-generation flexible electronics tailored to wearable technologies. Nevertheless, the uneven dispersion of carbon nanoparticles is the key to hindering the stretchability, high elasticity, and electrical conductivity of the material. Herein, ionic liquid 1-vinyl- 3-butyl imidazole bromide ([VBlm]Br) and polyacrylamide/sodium alginate (PAM/SA) were selected to form a new copolymerized hydrogel to improve the dispersion of conductive graphite (KS- 6) in the hydrogel. Due to the existence of an electron–ion conducting network and spatial cross-linking, making the prepared KS- 6/1.0[VBlm]Br/PAM/SA hydrogelhas good conductivity (22.39 mS/cm), tensile strain (467%), mechanical strength (73.64 kPa), toughness (161.09 kJ m⁻³), and adhesion (67.861 kPa). In addition, the flexible sensor based on the KS- 6/1.0[VBlm]Br/PAM/SA hydrogel also showed excellent performance, demonstrating that ionic liquids and carbon materials can synergistically enhance mechanical properties and electrical conductivity. The high-temperature sensing performance and high sensitivity (GF = 4.01) make the KS- 6/1.0[VBlm]Br/PAM/SA hydrogel an ideal candidate for building the next generation of gel-based strain sensor platforms.