Architecting Three-Dimensional Networks in Carbon Nanotube Buckypapers for Thermal Interface Materials

Abstract

Carbon nanotube (CNT) buckypaper, which has large specific surface area and tunable network structures, shows great potential in the application of heat dissipation for high power electronic devices. In this article, we report that the heat conduction in a buckypaper depends greatly on CNT network formation, in which CNT structures, lengths, and orientations are important issues. The buckypaper composed of multiwalled CNTs with large diameter (around 50 nm) and suitable length (1–10 μm) shows lower thermal impedance compared with those made by longer CNTs with smaller diameter. The thermal impedance of such buckypapers can be reduced to 0.27 cm2·K/W, lower than that of commercialized graphite foil and thermal grease. Thus, the buckypaper may serve as a promising candidate for advanced thermal interface materials. Detailed structural characterization indicates that the three-dimensional networks of buckypapers, with CNT orientations perpendicular to the surfaces, result in both the reduction of thermal contact resistance and the enhancement of heat conduction along the thickness.

Thermal conductivity of chirality-sorted carbon nanotube networks

“…26,27 Instead, our results are consistent with the view that the thermal conductivity of SWNT films depends more strongly on the SWNT junctions and the mass density of the films (which also controls the junctions and the SWNT segment lengths between junctions 28 ). Previously reported solution-processed SWNTs 29,30 found cross-plane thermal conductivity around 1.68 W m À1 K À1 for millimeter-thick SWNT films 29 and 2.24 W m À1 K À1 for MWNT films 30 with mass densities around 0.47 g/cm 3 . (The cross-plane thermal conductivity is expected to be lower due to the layering of SWNTs during the assembly process.)…”

Solder–Graphite Network Composite Sheets as High-Performance Thermal Interface Materials

“…31 A value of 3.7 9 10 4 W/(m 2 K) has been reported for a carbon nanotube paper. 55 A value of 6.85 9 10 4 W/(m 2 K) has been reported for vertically aligned carbon nanotube arrays synthesized on a bulk aluminum alloy. 17 For a bilayer aligned carbon nanotube TIM, 16 the thermal contact conductance is up to 11.39 9 10 4 W/(m 2 K) and the thermal conductivity is up to 19.75 W/(m K).…”

“…A very high value of the thermal conductivity [67 W/(m K)] has been reported for tin nanowires, but the thermal contact conductance for tin nanowires [5.0 9 10 4 W/(m 2 K)] is less than that [12][13][14][15][16][17][18][19][20][55][56][57] and nanofibers 58 have received much recent attention in relation to their potential as TIMs. A thermal contact conductance of 1.6 9 10 4 W/(m 2 K) has been reported for a carbon nanotube adhesive grease.…”

Electrically insulating POE/BN elastomeric composites with high through-plane thermal conductivity fabricated by two-roll milling and hot compression

“…For example, pure graphene films with a high in-plane thermal conductivity of 1940±113 W m −1 K −1 have been fabricated [31]. [47][48][49], and constructing a segregated structure [5,[50][51][52]. Vertically aliened CNT (VACNT) composites fabricating by the CVD method can provide a high through-plane thermal conductivity and can be used as TIMs [53].…”