Multi-functional self-healing polyurethane elastomer based on chair conformation for strain sensors

To address the diverse and complex application environments encountered today, the performance requirements for flexible sensing materials have become increasingly stringent. Traditional flexible sensing materials, which typically possess only excellent mechanical properties, can no longer meet these demands. We now seek materials that exhibit a range of additional features, including self-healing capabilities, biodegradability and good biocompatibility, to enhance the overall functionality and versatility of flexible sensors. This study successfully synthesized poly(carbonate-chair cyclohexane-urethane) (PCCU) with stable mechanical properties by incorporating a chair conformation structure and dynamic disulfide bonds into the polyurethane backbone. The resulting material demonstrated self-healing capability, antibacterial properties, recyclability, degradability, and biocompatibility. The chair conformation enhanced the material's fatigue resistance and promoted molecular chain mobility, thereby facilitating self-repairing properties. The synthesized polyurethane exhibited high tensile strength (15.09 MPa), high elongation at break (910%), a self-repairing efficiency of 92.75%, low dissipation efficiency (38.46%), 25% mass reduction after 8 weeks of degradation, and efficient antibacterial activity against Staphylococcus aureus and Escherichia coli (92.34% and 88.41%, respectively), with no cytotoxic effects observed. Finally, the polyurethane was encapsulated with conductive ink to validate its sensing capabilities through motion monitoring. This multifunctional polyurethane elastomer enhances the functionality of flexible electronic sensing materials and demonstrates potential applications across multiple domains. This study introduces a polyurethane urea-based flexible sensor material with self-healing, antibacterial, degradable and biocompatible properties. Its multifunctionality makes it ideal for sustainable wearable electronics.