Core-sheath smart polymer fiber composites with high elasticity and thermal conductivity

Thermal conductive polymer fibers have broad development prospects because of its excellent thermal and mechanical properties. However, currently reported polymer fibers cannot simultaneously possess high thermal conductivity and high resilience, which greatly limits the application of thermal conductive polymer fibers. Therefore, preparing fibers with high thermal conductivity and high resilience is extremely challenging. The thermoplastic polyurethane/boron nitride liquid metal (TPU/BN-LMs) fiber with core sheath structure is prepared by coaxial wet spinning technology, the boron nitride (BN) doped in thermoplastic polyurethane elastomer (TPU) as sheath and the liquid metal (LMs) as core. The maximum tensile strength of the fiber is 3.9 MPa, and the elongation can reach 400%. After multiple cycles of stretching, it can return to its original state. In addition, the thermal conductivity of the fiber in the horizontal direction and the vertical direction are 10.0 W m-1 K-1 and 4.6 W m-1 K-1, respectively. This work solves the current problem of high thermal conductivity and high resilience of thermally conductive polymer fibers that are difficult to be compatible. And it provides a new research idea for the design and preparation of new high thermal conductivity and high resilience polymer fiber materials.