Core-Sheath Heterogenous Interlocked Stretchable Conductive Fiber Induced by Adhesive MXene Modulated Interfacial Soldering

Whereas high electrical conductivity and mechanical stretchability are both essentially required for flexible electronics, simultaneously achieving them remains a great challenge due to the "trade-off" effect. Herein, an ultrastretchable conductor with core-sheath heterogeneous interlocked structure was developed, induced by interfacial soldering silver nanowires (AgNWs) which gradually evolved into elastic conductive fiber. Adhesive polydopamine-functionalized MXene (PDM) was proposed as an interfacial solder to assemble AgNWs along fibers while induced strong cold-welding effect soldered them into superelastic interconnected network. In situ coaxial heterogeneous interlocking between core AgNWs and sheath PDM network gradually formed during the interfacial soldering process, which enables elastic conductor simultaneously owning large mechanical stretchability and high electrical conductivity. Stretchable conductive fiber with core-sheath heterogeneous interlocking structure not only exhibits excellent electrical conductivity (1.13 × 10⁵ S/m) but also could maintain stability (ΔR/R₀ < 0.19) even under large mechanical deformations (300%). Ultrastretchable fibrous conductor with core-sheath heterogeneous interlocked microstructure induced by adhesive PDM interfacial soldering holds great promise in soft electronics.