Multifunctional Synergistic Design of Self-Healable Polyurethane-Based Flexible Sensors: From Molecular Engineering to Device Integration

Abstract

Self-healing flexible sensors can extend device lifetime and preserve reliable signal transduction after mechanical damage. As their applications broaden from health monitoring to human–machine interfaces and soft robotics, design priorities are shifting beyond crack closure toward the coordinated recovery of mechanical integrity, interfacial adhesion, conductive pathways, and device function. Polyurethane is particularly well suited to this objective because its segmented architecture enables tunable microphase separation and the incorporation of diverse dynamic interactions. Nevertheless, a systematic understanding of how molecular design and multifunctional integration determine device-level performance in self-healing polyurethane-based flexible sensors (SFPUFSs) remains lacking. This review examines recent advances in SFPUFS through a framework linking molecular engineering to device integration. Emphasis is placed on dynamic network design, healing-window regulation, and conductive-pathway reconstruction, as well as their roles in integrating self-adhesion, shape memory, antibacterial and antifouling properties, recyclability, and degradability. Representative applications in epidermal electronics, motion monitoring, soft robotics, and sustainable devices are evaluated, followed by a discussion of the key challenges in achieving functional synergy, reliable device-level recovery, and practical implementation.