Gradient Structure Construction of High Thermal Conductivity Polyurethane/Boron Nitride Composite Fiber Membrane for Thermal Management.

Accompanied by the rapid progress of the digital era and the continuous innovation of material science and technology, wearable electronic devices are widely used in various industries due to their excellent portability and flexibility. However, the problem of heat accumulation not only restricts the use of electronic devices but also poses potential safety risks for users. Therefore, there is an urgent need to study and develop thermal management materials applied to wearable devices to meet the demands of highly integrated wearable electronic systems. In this study, we report a method of combining functional boron nitride (FBN) and polyurethane (PU) through electrostatic spinning technology and gradient structure design, which ultimately results in multilayer structured FBN/PU composite fiber membranes with excellent thermal conductivity (2.96 W·m·K) and mechanical properties (The tensile strength, Young's modulus, and toughness were up to 12.03 MPa, 86.37 MPa and 15.02 MJ·m, respectively). The gradient structure design significantly improves the thermal conductivity and mechanical properties of the composite fiber membrane. The multilayer structured composite fiber membrane has high thermal conductivity and high mechanical properties and has potential application and development prospects in the thermal management of wearable electronic devices.