Interface‐Encoded Dynamic Covalent Crosslinking Enables Ultra‐Stretchable, Signal‐Stable Conductive Elastomers

ABSTRACT Conductive composite elastomers for soft electronics are often constrained by a fundamental trade‐off: weak filler–matrix adhesion leads to interfacial defects, stress concentration, and signal instability under dynamic strain, whereas conventional covalent “locking” improves adhesion at the cost of elasticity and stretchability. Here, we report a dynamic covalent interface engineering strategy that resolves this conflict by converting the filler–matrix boundary into a reconfigurable, stress‐dissipative covalent junction. Lipoic‐acid‐functionalized carbon nanofibers (CNFs) serve as nanoscale multi‐point crosslinkers within a polylipoic‐acid‐based elastomer, where surface‐grafted 1,2‐dithiolane rings undergo reversible disulfide exchange with the matrix to strengthen stress transfer while preserving network mobility. The resulting bio‐based conductive elastomers exhibit ultra‐stretchability (∼4200%) with markedly enhanced toughness and up to three‐ to fivefold higher conductivity compared with unmodified‐CNF controls. They operate over an exceptionally wide sensing range (0%–3000% strain), delivering gauge factors up to 8.13 and ∼2× higher ΔR/R 0 amplitudes, together with highly reproducible, low‐hysteresis responses under repeated large‐strain deformation. DFT calculations support the interfacial mechanism by revealing strengthened disulfide‐mediated binding. Enabled by the same dynamic chemistry, the elastomers further show room‐temperature self‐healing and closed‐loop recyclability. This work establishes an interface‐encoded molecular design principle for ultra‐stretchable, electromechanically stable, and sustainable conductive elastomers.