LAUSR

The generation of stretchable conductors is a mandatory precondition for the next-generation electronic devices including flexible, wearable electronics, smart skins and bioinspired devices [1–4]. This new class of electronic materials takes up external mechanical deformations and maintains structural integrity and electronic performance throughout bending, folding and stretching processes. Although intense efforts have been devoted to the construction of stretchable conductors, large stretchability is still difficult to achieve. The traditional method is to generate wavy structure through releasing a pre-stretched elastic polymer substrate coated with conductive materials [1]. As pre-strains are limited as well as adhesive interactions between inorganic layer and elastic organic substrates are weak, this technology is restricted to extensions lower than 200%. Another very classical option is to blend conductive additives with elastic matrix materials, using ultrasonications or high-strength shear forces [2]. Herein, usually a rapid decay in electronic conductivity occurs during the stretching process due to demixing processes and aggregation of conductive additives. Among the various conductive building blocks, silver nanowires (AgNWs) have shown promising potentials because of their excellent electrical conductivity and mechanical resilience [3]. Using AgNWs as conductive additives, the previously reported materials can only endure small deformations due to the random dispersion of AgNWs into the substrates. On top of that, self-healing is another important feature tightly related with the reliability and sustainability in the use of stretchable conductors when overstressed [5], however, rare work has involved such a topic. To address these issues, a team led by Cong at Hefei University of Technology in collaboration with Yu’s group at the University of Science and Technology of China [4] recently reported a superstretchable conductor with outstanding self-healing capability through synergistic interaction of a pre-designed highly-ordered AgNW aerogel framework via dynamic Ag–S coordination chemistry to form the final elastic polymeric hydrogel network (Figure 1 (a, b)). The obtained composite shows a well-defined cellular architecture following three levels of hierarchy from nanoscopic to microscopic and further to macroscopic scales. It is exciting to see that this composite can endure a superhigh strain of 800% while the resistance varies only 20% at a strain of 100%. Irreversible resistance changes during stretching cycles are practically negligible, which is the major weakness of all classical solutions. These superior performances are attributed to effective crack energy dissipation mechanism through deforming the cellular structure and dissipating the external stress in the whole network. The composite also exhibits fast self-healing with a healing efficiency of 93%, which is based on the reversible Ag–S bonds. Impressively, the healed materials still show outstanding electromechanical performance (Figure 1(b–d)). These combined merits of large deformability, strong fatigue-resistance and unique self-healing ability make this composite to my knowledge the new gold standard among the reported stretchable conductors. To summarize, this in-