Molecular dynamics simulation of a nanofluidic energy absorption system: effects of the chiral vector of carbon nanotubes

Abstract

A Nanofluidic Energy Absorption System (NEAS) is a novel nanofluidic system with a small volume and weight. In this system, the input mechanical energy is converted to surface tension energy during liquid infiltration in the nanotube. The NEAS is made of a mixture of nanoporous material particles in a functional liquid. In this work, the effects of the chiral vector of a carbon nanotube (CNT) on the performance characteristics of the NEAS are investigated by using molecular dynamics simulation. For this purpose, six CNTs with different diameters for each type of armchair, zigzag and chiral, and several chiral CNTs with different chiral vectors (different values of indices (m,n)) are selected and studied. The results show that in the chiral CNTs, the contact angle shows the hydrophobicity of the CNT, and infiltration pressure is reduced by increasing the values of m and n (increasing the CNT diameter). Contact angle and infiltration pressure are decreased by almost 1.4% and 9% at all diameters, as the type of CNT is changed from chiral to zigzag and then to armchair. Absorbed energy density and efficiency are also decreased by increasing m and n and by changing the type of CNT from chiral to zigzag and then to armchair.

Transport Phenomena in Nano/Molecular Confinements

“…There is also a wide range of parametric studies about other relevant factors, for example, CNT diameter, ,− chirality, − and charge, ,,, which have helped further clarify the role of these parameters in water transport through CNTs. Similar parametric studies have also been conducted in MD simulations to investigate the influence of the surface effects on the nanoconfined liquid not restricted to those in CNTs. , For example, Dai et al .…”

Dynamics of water confined in a graphene nanochannel: dependence of friction on graphene chirality

“…Due to Liu et al's molecular dynamics simulations [27,28], the diffusivity of water confined in zigzag CNTs was much larger than that in armchair CNTs, and the mechanism of this phenomenon was explained in the fact that the activation energy of molecular diffusion in zigzag CNTs was greater than that in armchair CNTs. Ganjiani et al studied the effect of chiral vectors of CNTs on the performance characteristics of a nanofluidic energy absorption system and found similar dependence of water dynamic properties on the chirality [29]. Wei et al found that the friction coefficient of water inside CNTs and boron nitride nanotubes (BNNTs) exhibited different chirality-dependent friction behavior [30].…”