Directly measuring of thermal pulse transfer in one-dimensional highly aligned carbon nanotubes

Abstract

Using a simple and precise instrument system, we directly measured the thermo-physical properties of one-dimensional highly aligned carbon nanotubes (CNTs). A kind of CNT-based macroscopic materials named super aligned carbon nanotube (SACNT) buckypapers was measured in our experiment. We defined a new one-dimensional parameter, the “thermal transfer speed” to characterize the thermal damping mechanisms in the SACNT buckypapers. Our results indicated that the SACNT buckypapers with different densities have obviously different thermal transfer speeds. Furthermore, we found that the thermal transfer speed of high-density SACNT buckypapers may have an obvious damping factor along the CNTs aligned direction. The anisotropic thermal diffusivities of SACNT buckypapers could be calculated by the thermal transfer speeds. The thermal diffusivities obviously increase as the buckypaper-density increases. For parallel SACNT buckypapers, the thermal diffusivity could be as high as 562.2 ± 55.4 mm2/s. The thermal conductivities of these SACNT buckypapers were also calculated by the equation k = Cpαρ.

The influence of charging and discharging on the thermal properties of a carbon nanotube/polyaniline nanocomposite electrode

“…The method of thermal diffusivity measurement we utilized in this study is based on one-dimensional periodic heat transfer. 15,[23][24][25] The heat ux can be regarded as quasi-1D diffusion in the in-plane direction, due to the large length to width ratio. The one-dimensional Fourier equation is…”

“…The time phase difference is determined by the peaks of the waves, which are independent of the waveform. 25 The gure shows the obvious time phase difference and the different amplitudes of the two temperature waves. The temperature monitored by infrared laser thermometer I ranged from about 316 K to 440 K, with an amplitude of about 124 K. The temperature monitored by thermometer II ranged from about 310 K to 327 K, with an amplitude of about 17 K. The nal results relating to thermal diffusivity will be discussed together with those for thermal conductivity.…”

“…The thermal diffusivities of the CNT/PANI composites range from about 148 mm 2 s À1 to 212 mm 2 s À1 , which are close to the values for super-aligned CNTs. 25 The thermal diffusivities decrease almost linearly as the potential increases from À0.4 V to +0.4 V, while the thermal diffusivity of the sample under bias at À0.6 V is less than that under bias at À0.4 V, and that of the sample under bias at +0.6 V is larger than that under bias at +0.4 V. This curious phenomenon was repeatable, and another independent set of results is shown in ESI Fig. S1.…”

“…The values of the thermal conductivities are also close to those of super-aligned CNTs. 25 The thermal conductivities of the original two independent data sets are shown in ESI Fig. S2.…”

A Thermo-Electric Apparatus for Thermal Diffusivity and Thermal Conductivity Measurements

“…A TEC module is used as the heat source for the measurement platform. It is connected to a computer for program control, thereby achieving the dynamic operation of the sine-wave temperature [15][16][17][18]. The thermal conductivities of five common heat-conducting materials used in electronics, namely red copper, brass, silver, aluminium alloy (1050), and non-metallic aluminium nitride ceramic, are measured.…”