Carbon Nanotube Arrays with Cross-Linked Networks for Thermal Conductivity

Due to the weak interaction between adjacent carbon nanotubes in vertical carbon nanotube arrays (VACNT), the horizontal thermal conductivity of VACNT is low. To solve this problem, the randomly oriented secondary carbon nanotube was grown inside the carbon nanotube array by chemical vapor deposition method. The secondary carbon nanotube formed a crosslinking network in VACNT, which enhanced the horizontal thermal conductivity of VACNT. Theoretical simulation analysis shows that the secondary carbon nanotubes are able to disperse the heat conduction to the concentrated heat, thus effectively modulating the thermal conductivity of the carbon nanotube arrays along the horizontal direction. The test results show that the carbon nanotube array with a secondary growth time of 30 min has a denser network structure and its density is 0.149 g/cm³, which is 26.3% higher than that of VACNT (0.118 g/cm³). Its vertical thermal conductivity and horizontal thermal conductivity are as high as 10.9 W/(m·K) and 7.8 W/(m·K), respectively, and the horizontal thermal conductivity is enhanced by 231.6% compared with that of VACNT.