Stable n-Type Conducting Elastomer with High Stretchability and Electrical Conductivity

Stretchable n-type conducting polymers are crucial for advancing high-performance optoelectronic and bioelectronic devices, yet their development lags significantly behind that of p-type counterparts due to the intrinsic challenge of harmonizing electrical conductivity with mechanical compliance. Herein, a novel strategy is reported to engineer a high-performance n-type conductive elastomer by synergistically blending the n-type polymer poly(benzodifurandione) (PBFDO) with thermoplastic polyurethane (TPU) and modulating phase separation via the ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate. The resulting PBFDO/TPU/IL composites (PBTI) achieve an unprecedented combination of n-type electrical conductivity exceeding 200 S cm^-¹, fracture elongation surpassing 200%, and robust operational stability, outperforming existing stretchable n-type conductive polymers. The controlled phase-segregated morphology ensures efficient charge transport while maintaining elastomeric resilience, addressing the long-standing trade-off between conductivity and stretchability. PBTI is integrated with a p-type PEDOT:PSS-based elastomer to demonstrate its versatility in constructing a stretchable thermoelectric generator (TEG), which exhibits a reliable power output under mechanical deformation. Further applications in fire safety warnings and real-time human physiological monitoring underscore the material's practicality in adaptive wearable and implantable systems. This work breaks new ground in n-type stretchable conductors, paving the way for sophisticated bioelectronics and self-powered devices requiring balanced electronic and mechanical functionalities.