Carbon Nanotubes(CNTs) offer unique possibilities as fluid conduits with applications ranging from lab on a chip devices to encapsulation media for drug delivery. CNTs feature high mechanical strength, chemical and thermalstability and biocompatibility therefore they are promising candidates for nanodevice fabrication. Thermal gradients have been proposed as mechanism to drive particles, fullerenes and droplets inside CNTs. Here, by conducting Molecular Dynamics (MD) simulations, we study thermophoresis of water droplets inside CNTs. We systematically change the size of the droplets, the axial thermal gradient and CNT chirality. We find that the droplet motion in the armchair CNTs exhibits two clearly delimited stages, a regime wherein the droplet is accelerated and subsequently, a regime wherein the droplet moves with constant velocity. Inside the zig zag CNTs, the droplet accelerates during a very short time and then it moves with constant velocity. We compute the netforce during the droplet acceleration and find a correlation between the droplet acceleration and the magnitude of the thermal gradient without any dependence on the droplet size. Moreover, we conduct velocity constrained MD simulations to determine the friction and thermophoretic forces acting on the droplet.
|Title of host publication||Bulletin of the American Physical Society|
|Number of pages||1|
|Publisher||American Physical Society|
|Publication status||Published - 2016|
|Event||69th Annual Meeting of the APS Division of Fluid Dynamics - Portland, United States|
Duration: 20 Nov 2016 → 22 Nov 2016
|Conference||69th Annual Meeting of the APS Division of Fluid Dynamics|
|Period||20/11/2016 → 22/11/2016|
Zambrano, H., Walther, J. H., Oyarzua, E., & Rojano, A. (2016). Thermophoresis of water droplets inside carbon nanotubes. In Bulletin of the American Physical Society (Vol. 61). [E22.00006 ] American Physical Society.