A Highly Stretchable, Self-Healing Elastomer with Rate Sensing Capability Based on a Dynamic Dual Network.

Flexible sensing materials have attracted tremendous attention in recent years because of their potential applications in the fields of health monitoring, artificial intelligence, and so on. However, the preparation of rate sensing materials with self-healing performance is always a huge challenge. Herein, we first report the design and synthesis of a highly stretchable, recyclable, self-healing polysiloxane elastomer with rate sensing capability. The elastomer is composed of a dynamic dual network with boron/oxygen dative bonds and hydrogen bonds, which overcomes the structural instability of conventional solid-liquid materials. It exhibits certain adhesion, satisfactory mechanical robustness, and superior elongation at break (up to 1171%). After heating treatment at 80 °C for 2-4 h, the mechanical properties of damaged materials can be almost completely restored. Because of the "solid-liquid" property of the elastomer, it has irreplaceable functions which can sense different rates by resistance change after blending with multiwalled carbon nanotubes, principally in the range of 10 mm/min-150 mm/min. Especially, this rate sensing elastomer can be personalized by 3D printing at room temperature. This rate sensing strategy coupled with the introduction of dynamic dual-network structure is expected to help design advanced wearable devices for human rhythmic movement.