Highly thermally conductive and flexible nanocomposites prepared by integrating 1D/2D polyethyleneimine-modified boron nitride

Thermally conductive composites rely on efficient heat transfer networks. Here, we employ polyethyleneimine to modify 1D boron nitride nanotubes (BNNTs) and 2D boron nitride nanosheets (BNNSs) to improve their dispersion while enhancing the interfacial interaction between them and the matrix through amide bonds, hydrogen bonds, and Lewis acid-base interactions, thereby reducing interfacial thermal resistance. Moreover, the introduction of 1D BNNTs bridges 2D BNNSs, boosting the thermal conductivity network. This resulted in an enhanced thermal conductivity of the composite film by 17.8 %, reaching 28.71 W/(m·K) at a 30 wt% filler content. Coupled with satisfactory mechanical strength and thermal stability, this heat dissipation capability is highly valuable for applications.