A tough, anti-freezing and conductive nanocomposite interpenetrated organohydrogel mediated by hydrogen bonding

Abstract

Conductive hydrogels have received extensive attention in the field of stretchable electric materials due to their good flexibility and conductivity. However, inferior strength and poor freezing tolerance of hydrogels suppress their long-term stability when used under harsh conditions. It remains challenging to design a tough, anti-freezing and conductive gel. Herein, we constructed a nanocomposite interpenetrated organohydrogel in ethylene glycol (EG)/H₂O/potassium chloride (KCl), which incorporated two kinds of crosslinkers: a chemical crosslinker formed via the crosslinking of acrylamide (AM) in the presence of vinyl-modified silica nanoparticles (VSNPs), and a physical crosslinker based on intermolecular hydrogen bonding and poly(vinyl alcohol) microcrystals formed during freeze–thaw cycling. Owing to their dual-crosslinked network structure, anti-freezing ethylene glycol (EG)/H₂O binary solvent and conductive KCl, the nanocomposite interpenetrated organohydrogels exhibited excellent mechanical properties, low-temperature tolerance and good conductivity. Tensile tests showed that the addition of ethylene glycol exerted a pronounced influence on elevating the tensile strength of the nanocomposite interpenetrated organohydrogels, which increased from 0.90 to 1.29 MPa. Impressively, the ions of KCl exerted a significant influence on both the conductivity (from 1.45 × 10⁻³ to 1.53 × 10⁻² S cm⁻¹) and the tensile strength (from 1.29 to 1.85 MPa), which probably resulted from the formation of a hydrophobic domain. This work provides a feasible method by which to construct a mechanically strong, low-temperature tolerant and conductive composite gel, which would find applications as electronic skins, sensors and intelligent devices.