Highly stretchable, transparent and room-temperature self-healable polydimethylsiloxane elastomer for bending sensor

Highly stretchable and self-healable elastomers are attractive for a variety of applications in the fields of electrical skin and wearable devices. Herein, we proposed a simple one-pot two-step approach to synthesize room-temperature self-healable polydimethylsiloxane (PDMS) elastomers. Excess aminopropyl terminated polydimethylsiloxane was firstly reacted with isophorone diisocyanate to synthesize amino-terminated PDMS with incorporated ureido groups, followed by further reaction with terephthalaldehyde as chain extender to yield self-healing PDMS elastomers. The obtained elastomer exhibited high stretchability of 1670% and transmittance of 92%. Owing to the dynamic intermolecular hydrogen bonds, reversible imine bonds and highly flexible SiO chains, the elastomer showed excellent self-healing capability with a healing efficiency of 95% after healing at room temperature for 24 h. Even in water and artificial sweat, the healing efficiencies also reached 89% and 78%, respectively. In addition, the elastomer supported triple-layer bending sensor was fabricated with a sandwiched hydroxylated multiwalled carbon nanotubes (MWCNTs-OH) film and successfully applied for detecting human motions. Interestingly, the cut sensor was able to be recovered for working after being irradiated under sunlight for only 10 min. Our method to synthesize highly stretchable, transparent and self-healing elastomers is simple and the reaction can be carried out at room temperature, which is beneficial for the large-scale production and the further practical application in functional electronics.