Enhanced thermal conductivity and dimensional stability of flexible polyimide nanocomposite film by addition of functionalized graphene oxide

Polyimide (PI) nanocomposites with both enhanced thermal conductivity and dimensional stability were achieved by incorporating glycidyl methacrylate‐grafted graphene oxide (g‐GO) in the PI matrix. The PI/g‐GO nanocomposites exhibited linear enhancement in thermal conductivity when the amount of incorporated g‐GO was less than 10 wt%. With the addition of 10 wt% of g‐GO to PI (PI/g‐GO‐10), the thermal conductivity increased to 0.81 W m^?1 K^?1 compared to 0.13 W m^?1 K^?1 for pure PI. Moreover, the PI/g‐GO‐10 composite exhibited a low coefficient of thermal expansion (CTE) of 29 ppm °C^?1. The values of CTE and thermal conductivity continuously decreased and increased, respectively, as the g‐GO content increased to 20 wt%. Combined with excellent thermal stability and high mechanical strength, the highly thermally conducting PI/g‐GO‐10 nanocomposite is a potential substrate material for modern flexible printed circuits requiring efficient heat transfer capability.