Researchers from Vrije Universiteit Brussel and Imec in Belgium have developed a stretchable, flexible sensor with remarkable self-healing properties, offering enhanced durability for wearables and soft robotics applications, tells IEEE Spectrum. This innovative sensor employs a polymer built with Diels–Alder reversible crosslinks, allowing it to restore its structural integrity after being cut completely in half—all while maintaining near-original performance levels.
The self-healing mechanism works through dynamic chemical bonding: when damaged, the broken bonds become reactive and reform once the severed parts are realigned, effectively restoring the polymer network. At room temperature, the sensor heals in about 24 hours, and this can be reduced to 4 hours with mild heating at 60°C.
Embedded within the polymer matrix is a liquid metal conductor (Galinstan). Despite severe damage, the liquid metal remains largely contained due to surface oxidation forming a protective barrier, minimizing leakage and ensuring electrical continuity.
Performance testing reveals impressive resilience: a pristine sensor subjected to 800 cycles of stretching experienced less than 5% signal drift, while a sensor that had been cut and healed still showed under 10% drift across the same usage. Even after six cycles of being stretched to failure and then healed, the sensor retained 80% of its functionality.
Beyond robust recovery, the design also incorporates sustainability: over 95% of the sensor materials can be recovered and recycled at end-of-life. The team has launched a spin-off, Valence Technologies, to commercialize this technology for applications ranging from medical rehabilitation and sports monitoring to soft robotics. Their next steps include scaling up to full-body motion capture systems and evaluating long-term durability under real-world conditions, such as exposure to sweat.