Carbon nanotubes based engineering materials for thermal management applications

Abstract

We developed innovative solutions for reaching high performance in carbon-nanotube-filled engineering materials. Electrospinning was applied to improve the thermal conductivity in polymer composites via the alignment of nanotubes in a polymer matrix. Alignment was achieved by flow-confinement and charge-induced alignment during electrospinning. Additionally, the use of liquid crystal polymer as a matrix increased the degree of alignment leading to the remarkable increase of the thermal conductivity in composites by a factor 33. We developed the reduction from method to produce metal-matrix composites filled with carbon nanotubes. We were able to engineer the coefficient of thermal expansion (CTE) of the copper composite, for example 3 wt% of carbon nanotubes added to copper yielded CTEs comparable with ceramics and semiconductors. In situ thermal polymerization of natural oils (plant and fish) was applied to produce nanotubes-based thermal greases. This method creates novel, environmentally friendly thermal grease with excellent thermal conductivity (increased by a factor 12), that is easy to handle compound and to remove. Such thermal greases can be applied to surfaces by various methods, including screen printing, and demonstrate good thermal stability, reduced thermal expansion, and no pumping-out effect.