Thermal conductivity of liquid/carbon nanotube core-shell nanocomposites

Abstract

Hollow carbon nanotubes (CNTs) were impregnated with an ionic liquid, resulting in a composite coreshell nanostructure. Liquid infusion was verified by transmission electron microscopy and rigorous observations unveiled that the nanocomposite is stable, i.e. liquid did not evaporate owing to its low vapor pressure. A series of individual nanostructures were attached on T-type heat sensors and their thermal behavior was evaluated. The liquid core was found to reduce the thermal conductivity of the base structure, CNT, from ca. 28 W/mK to ca. 15 W/mK. These findings could contribute to a better understanding of nanoscale thermal science and potentially to applications such as nanodevices thermal management and thermoelectric devices.

Impedance of Thermal Conduction from Nanoconfined Water in Carbon Nanotube Single-Digit Nanopores

“…This corroborates earlier estimates from substrate-supported CNTs and suggests that filling-induced modulations of nanotube thermal properties are not limited to specific endohedral species such as fullerenes . Together with recent experimental results, , our findings instead suggest that interior molecules may generally act to impede heat transfer in nanotubes through acoustic phonon scattering. The overall axial thermal conductivity could still be enhanced with respect to an empty tube if the confined molecules themselves allowed for efficient axial heat transfer (scenario 1 in Figure a).…”

“…The overall axial thermal conductivity could still be enhanced with respect to an empty tube if the confined molecules themselves allowed for efficient axial heat transfer (scenario 1 in Figure a). In the CNTs studied so far, this seems not to be the case for water (this work and ref ), fullerenes, and certain ionic liquids …”

“…Water filling has been suggested to similarly reduce the thermal conductivity of CNTs, but experimental verification remains challenging. For large multiwalled CNTs with inner diameters on the order of 50 nm, a reduction in κ upon filling with an ionic liquid has been measured . However, the thermal properties of individual SWCNTs are much harder to assess due to difficulties in handling and thermal decoupling from the environment, let alone challenges related to the fluid filling of these nanoscale objects .…”

Concurrent thermal conductivity measurement and internal structure observation of individual one-dimensional materials using scanning transmission electron microscopy

“…(1), we measured the total thermal resistance for CNT-a and CNT-b to be (8.9 ± 5.0)×10 7 K/W and (3.3 ± 0.4)×10 7 K/W, respectively. Although we cannot separate the thermal contact resistance (Rt,c) in our measurement, Rt,c is negligible as reported in the literature with similar contact conditions, 8,9,34,41 since we bonded the CNT firmly with the sensor and the heat sink using EBID. Thus, we took Rt,c in Eq.…”

“…Here we used the shell crosssectional area of the CNT for the thermal conductivity calculation, which is the same as the previous measurements on cup-stacked CNTs. 41,42 As shown in Fig. 3 One concern about our method is whether the electron beam can damage the sample, since the electron beam can introduce defects in graphene.…”