Enhanced Thermal Conductivity of Nanodiamond Nanosheets/Polymer Nanofiber Composite Films by Uniaxial and Coaxial Electrospinning: Implications for Thermal Management of Nanodevices

Nanotechnology is gradually applied to the preparation of heat dissipation materials with the miniaturization of electronic devices. Electrospinning technology has received extensive attention due to its unique advantages in constructing continuous nanofibers. In this work, uniaxial-polyvinyl alcohol/nanodiamond (U-PVA/ND) and coaxial-polyvinyl alcohol/nanodiamond (C-PVA/ND) composite fiber films with different microscopic morphologies were constructed by uniaxial and coaxial electrospinning. The results show that the thermal conductivities of U-PVA/ND and C-PVA/ND composite fibers with 60 wt % ND content are 71.3 and 85.3 W m–1 K–1, respectively, which are 171.2 and 205.1 times greater than that of the pure PVA fiber film. In addition, the maximum thermal decomposition temperature (Tmax) and volume resistivity of the C-PVA/ND composite fiber film were 364.3 °C and 2.29 × 1015 Ω·cm, respectively, demonstrating the excellent thermal stability and electrical insulation of the composite fiber film. This experiment results provide strong evidences of electrospinning technology for the preparation of highly thermally conductive composites. So, thermally conductive films can be used as the outer layer of electronic components to accelerate their heat dissipation and extend their service life.