Carbon Nanotube/Polymer Coaxial Cables with Strong Interface for Damping Composites and Stretchable Conductors

Abstract Carbon nanotube (CNT) fibers have the potential to serve as continuous nano‐fillers for structural and functional composite materials, yet there exists the interfacial problem that has hindered the development of continuous fiber reinforced composites for a long time. Here, a method to overcome this challenge by coating a thick CNT sponge around a single‐walled nanotube (SWNT) fiber is presented, and then infiltrating polymers into the sponge to construct a SWNT@polymer coaxial cable. It has been found that the residual stress‐induced deposition of amorphous carbon as an intermediate layer between the underlying SWNT fiber and the subsequently coated multi‐walled nanotube (MWNT) sponge plays a key role in interfacial properties, and together with well‐dispersed CNT in the polymer matrix, a superior interfacial shear strength (>12 MPa), enhanced tensile strength and toughness is achieved. These coaxial cables demonstrate high mechanical damping ability and can serve as stretchable conductors maintaining high electrical conductivity during large‐strain cyclic deformation. These results indicate a promising route toward developing continuous CNT fiber‐based composites with wide applications as structural and multi‐functional composite materials.