Stretchable, Conductive, and Self-Healing Hydrogel with Super Metal Adhesion

Currently, adhesive and self-healable hydrogels have highlighted their potential in tissue adhesives, sealants, and implantable electronic devices. For electronic device adhesives, a combination of adhesive, conductive, and self-healing properties is required. Here, we demonstrated a one-pot synthesis method of a novel self-healing hydrogel (named GO(x)SPNB) with various ratios of graphene oxide to soluble starch and poly(sodium 4-vinyl-benzenesulfonate-co-N-(2-(methacryloyloxy)ethyl)-N,N-dimethylbutan-l-aminium bromide) by a gamma-radiation technique. The resultant hydrogel based on a totally physical cross-linking network exhibits fast automatic self-healing ability, nontoxicity, ionic conductivity about 10.5 mS dm(-1), and super highly reusable metal adhesion with 60.5 MPa adhesive strength to the copper plates at room temperature, nearly one magnitude larger than other reversible adhesives that have been reported. Meanwhile, it also shows extreme adhesive strength to some organic substrates, such as porcine skin (130.70 kPa) which is the highest strength to date. This self-healable adhesive hydrogel, especially for metal substrates, has great potential in hydrogel glues for the design and fabrication of smart electronic device adhesives.