Supersoft, Stretchable, Tough, and Adhesive Elastomers with Dual Metal‐Ionic Crosslinked Double‐Network Structure

Abstract Soft, stretchable, tough, and adhesive elastomers are developed based on the metal‐ionic crosslinked double network structure, where the metal ion coordination of sulfonated poly(phenylene oxide) (SPPO) is used for the first network and the soft chemical crosslinked poly(ethyl acrylate) (PEA) is used for the second network. The influence of SPPO content on the tensile, cyclic tensile, adhesive, and rheological behavior of the elastomers is systematically investigated. It is observed that the elastomers are immensely soft and stretchable with tunable modulus from 0.038 to 0.086 MPa, fracture strain of ≈1400%, fracture stress in the range 0.20–1.2 MPa, work of extension of 0.72–5.6 MJ m−3, fast self‐recovery of 5 s after experiencing 200% strain, and robust adhesive behavior on glass substrates with interface debonding energy ≈35.2 J m−2. The mechanical behavior of the double‐network elastomers at the macroscopic scale is related to the dynamic breaking and reforming of the metal‐ion coordination at the molecular scale in the first network. This study provides a facile approach for the synthesis of elastomers with multidimensional mechanical behavior and broadens the applications of the elastomers in the field of flexible electronic devices, soft robotics, among others.