Constructing interconnected network of MWCNT and BNNS in electrospun TPU films: Achieving excellent thermal conduction yet electrical insulation properties

Thermal management materials with excellent thermal conductivity (TC) and electrical insulation are highly favorable in the modern integrated electronic areas. Herein, an interconnected network of multi-walled carbon nanotubes@boron nitride nanoplatelets (MWCNT@BNNS) in thermoplastic polyurethane (TPU) composite film was constructed through the electrospinning and electrospraying method, followed by hot-pressing process. Most of MWCNT were oriented along the electrospun TPU fibers and wrapped inside the fibers to maintain the insulation properties at the content of 5 wt%. Furthermore, BNNS were attached onto the surface of 1D TPU/5MWCNT fibers and connected with MWCNT to achieve both high TC and excellent electrical insulation. The obtained TPU/5MWCNT@40BNNS composite film exhibited excellent in-plane TC of 9.99 W/(m·K), indicating the excellent heat dissipation capacity than TPU@40BNNS composite films. Additionally, the composite film also displayed remarkable electrical insulating properties (about 1013 Ω cm) and excellent flexibility. This work provides more immense potential applications in the next-generation flexible electronic equipment.