A mechanically robust self-healing polysiloxane via Fe3+-dopamine metal coordination for flexible sensors

Abstract

In recent years, wearable electronic devices based on polydimethylsiloxane (PDMS) have garnered increasing attention. However, the limited mechanical strength of PDMS itself and its poor self-healing properties after prolonged use restrict its application in flexible sensors. Here, we propose a novel approach to successfully prepare a self-healing polydimethylsiloxane material (Si-DOPA_x-Fe_y) with enhanced mechanical properties by introducing a metallic coordination network. The obtained Si-DOPA_x-Fe_y exhibited a maximum tensile strength of 652 kPa and an elongation at break of 133%. When fracture damage occurred, Si-DOPA₃-Fe_0.6 achieved a self-healing efficiency of 90.3% after 8 hours of repair at room temperature. Based on Si-DOPA₃-Fe_0.6, we combined it with AgNWs to prepare Si-DOPA₃-Fe_0.6-AgNWs for measuring human physiological activity in real time. According to experimental results, Si-DOPA₃-Fe_0.6-AgNWs had a sensitivity of 4.6 and a linear response coefficient R² of 0.999 within the 0–60% strain range, indicating good stability and sensitivity for this flexible sensor. This research not only advances the development of polysiloxanes in flexible electronic sensing but also holds promise for broad applications in medical health monitoring and human–machine interface fields, laying the foundation for next-generation smart material development.