Thread-analogous elastic fibers with liquid metal core by drawing at room temperature for multifunctional smart textiles

Stretchable and elastic conductive fibers with liquid metal core are appealing for integration into electronic fabrics and clothing, owing to their inherent electrical conductivity even under strain. Previously, injecting liquid metal into core of hollow elastic fiber has been utilized to fabricate conductive fibers, however, hydrodynamics limits the extent to which metals can be injected, thus limiting length and cross-sectional area. Although direct printing and spinning methods using coaxial needles have been utilized to fabricate long and thin polymer-encased liquid metal fibers via single step, various parameters including extrusion rate along with viscosity and surface tension of liquid metal and polymeric shell, needs to be considered. Herein, we introduce a simple and facile method for fabricating thread analogous conductive fibers by plastically deforming liquid metal injected polymeric shell via drawing at room temperature. This simple yet effective process generates long conductive fibers with narrow cross-sectional area of the liquid metal wire continuously formed along its length. The obtained fiber can withstand deformation arising from daily activities while maintaining excellent electrical performance, thus can be used for fabricating smart textiles serving multitude of purposes.