Flexible and high thermal conductivity thin films based on polymer: Aminated multi-walled carbon nanotubes/micro-aluminum nitride hybrid composites

Multi-walled carbon nanotubes functionalized with amino groups (MWCNT-NH2) were prepared via the chemical modification of the carboxyl groups introduced on the surface of MWCNT. The synthesized materials and untreated micro-aluminum nitride (micro-AlN) particles were embedded in a polymer resin, viz, epoxy-terminated dimethyl siloxane. The thermal diffusivity and conductivity of all of the composites continuously improved with increasing the content of fillers. A thermal conductivity of 3.81 W/mK was achieved at an MWCNT-NH2 loading of 3 wt% and micro-AlN loading of 70 wt% while their flexibility was maintained. This result is due to the high aspect ratio of the MWCNT-NH2 which allows a heat conductive percolation network to be established between the micro-AlN particles. Also, all of the composites fabricated by the optimized process endured about 200,000 bending cycles without rupturing or losing their thermal conductivity. (c) 2012 Elsevier Ltd. All rights reserved.