Nanographite/nanosilica-filled dopamine-containing polyacrylamide hydrogels of temperature-sensitive photothermal responses

Conductive hydrogels are of significant interest because of their important applications in flexible electronics, energy storage, and human-computer interaction. However, the deficiencies of weak electrical conductivity and mechanical properties seriously hinder the applications of conductive hydrogels in this frontier area. In this research, conductive hydrogels with high electrical conductivity, excellent self-recovery properties and outstanding photothermal effects are prepared by the synergistic interaction of dopamine, silica nanoparticles, graphite nano-powder (Grn) and polyacrylamide chains. The effects of Grn and temperature on the conductivity of the hydrogels were investigated in detail. The hydrogels feature the highest conductivity (7.2 mS/cm) and even 9.1 mS/cm at 60 °C due to the excellent thermal and electrical conductivity of the Grn, which also endows the hydrogels with excellent photothermal effect and stable energy storage properties. Notably, the catechol group of dopamine (DA) leads to excellent self-adhesive properties of the conductive hydrogels. The use of silicon dioxide nanoparticles (SNs) allows the conductive hydrogels to obtain favorable toughness as well as self-recovery properties. This provides a broad prospect for the applications of conductive hydrogels in practice.