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Novel three-dimensional carbon nanotube networks as high performance thermal interface materials

Kong, Qinyu, Bodelot, Laurence, Lebental, Bérengère, Lim, Yu Dian, Shiau, Li Lynn, Gusarov, Boris, Tan, Chong Wei, Liang, Kun, Lu, Congxiang, Tan, Chuan Seng, Coquet, Philippe, Tay, Beng Kang
Carbon 2018 v.132 pp. 359-369
air, carbon, carbon nanotubes, catalysts, crosslinking, heat transfer, image analysis, models, temperature, thermal conductivity
Vertically aligned carbon nanotube (VACNT) arrays are considered as promising thermal interface materials (TIMs) due to their superior out-of-plane thermal conductivities. However the air gaps between adjacent CNTs within the CNT array hinder the in-plane heat transfer, thus significantly degrading the thermal performance of VACNT-based TIMs. To improve the in-plane thermal conduction of VACNT arrays, we propose a novel three dimensional CNT (3D CNT) network structure, where VACNTs are cross-linked by randomly-oriented secondary CNTs. Three different catalyst preparation methods for the secondary CNT growth are compared in terms of their ability to produce a dense network of secondary CNTs. The 3D CNT network grown using the chemical impregnation method shows a denser network structure, and thus is chosen for further thermal characterization. The temperature fields of the corresponding 3D CNT network under different heating powers are recorded using a 15 μm-resolution infrared thermal imaging system. The in-plane thermal conductivity is then derived from these fields using numerical fitting with a 3D heat diffusion model. We find that the in-plane thermal conductivity of the 3D CNT network is 5.40 ± 0.92 W/mK, at least 30 times higher than the thermal conductivity of the primary VACNT array used to grow the 3D CNT network.