Researchers in China have developed polyurethane-based conductive fibers that can stretch to five times their original length, self-heal after being cut and support touch-responsive illuminated textiles.
The fibers were produced by wet-spinning a mixture of polyurethane and an ionic liquid. The resulting interconnected ion-conducting network maintained pathways for ion movement as the surrounding PU chains underwent substantial deformation.
Researchers from Donghua University, Jilin University and China FAW Group incorporated the fibers into alternating-current electroluminescent devices intended for wearable displays and human-machine interfaces.
The fibers achieved an elongation of 500% and ionic conductivity of 2.8 × 10−6 S/cm. The research team said they retained stable mechanical performance over repeated stretching cycles without obvious degradation.
The ionic liquid dispersed within the elastomeric PU matrix allowed the conductive network to accommodate movement without interrupting ion transport. This enabled the devices to continue emitting light while undergoing large deformations.
The researchers also demonstrated touch-responsive illumination using capacitive coupling between the wearer's body and the fiber. Touching the device altered its electrical field and triggered a visible response without requiring a conventional mechanical switch.
After a fiber was severed, dynamic interactions within the polyurethane allowed the cut surfaces to reconnect at room temperature. The ionic liquid then re-established the internal conductive pathway, restoring both electrical conduction and light-emitting performance.
The team said conventional electroluminescent fibers often struggle to combine stretchability, mechanical durability and stable light output. Damage to a conductive pathway can permanently disable these devices, while repeated movement may cause cracking, delamination or loss of conductivity.
The researchers believe the combination of elasticity, self-healing and touch responsiveness could make the PU fibers suitable for smart clothing, flexible displays and interactive human-machine interfaces.
The work remains at the laboratory stage, and the researchers did not report commercial-scale manufacturing trials, wash testing or long-term performance under normal garment-use conditions.
The study, "Ultrastretchable and mechanically robust ionic conductive fibers enable wearable electroluminescent electronics with large deformation tolerance and body-capacitive coupling," was published in the Journal of Materials Science on August 11.