Strain-Resilient Integrated Conductive Elastomer with Stable Conductivity via Grafting and Blending for Flexible Sensing and Self-Adhesive Dry Electrocardiogram Monitoring Electrode

Integrated conductive elastomers have attracted significant attention for their potential in flexible wearable electronics, electrocardiogram (ECG) monitoring, and other fields due to their unique combination of elasticity and electrical functionality. Conventional flexible conductors often suffer from environmental instability, such as solvent leakage in gels, or conductivity degradation under mechanical deformation in filler-based elastomers. To realize practical applications in flexible electronics, conductive elastomers must possess stable conductivity under stretching, as well as superior deformability and resilience. Moreover, addressing the trade-off between electrical performance and mechanical properties of conductive elastomers is still challenging. In this study, the solid polymer electrolyte (SPE) polyethylene glycol (PEG) was incorporated into a butyl acrylate (BA) elastomer via grafting and blending to fabricate integrated conductive elastomers. Furthermore, based on the multi-bond network (MBN) concept, 1-vinylimidazole (VI) was copolymerized into the butyl acrylate elastomer backbone to form Zn2+-VI coordination, which further enhanced the mechanical properties of the conductive elastomer. The PEGMA chains grafted onto the BA ensure excellent compatibility between P(BA-co-VI)-g-PEGMA/Zn2+ and the blended free PEG chains, thereby inhibiting phase separation and facilitating Li+ transport. Consequently, a transparent integrated conductive elastomer was obtained with a stable conductivity as high as 1.60 × 10-2 S m-1, which is comparable to that of a pure PEG-Li+ system. Its conductivity can remain near 1.5 × 10-2 S m-1 even under an extremely large strain of 1000%. The resulting elastomer exhibited an extremely high elongation at break exceeding 1800% and outstanding resilience, showing a residual strain of only 130% after five cycles at 1000% strain and rapid recovery within 30 min. Furthermore, the conductive elastomer demonstrated remarkable stability and sensitivity in strain sensing, while also serving as a dry electrode for high-quality ECG signal collection, highlighting its considerable potential for flexible sensing technologies and health monitoring.