jp7b11657_si_001.pdf (1.05 MB)
Effects of Electrostatic Interaction and Chirality on the Friction Coefficient of Water Flow Inside Single-Walled Carbon Nanotubes and Boron Nitride Nanotubes
journal contribution
posted on 2018-02-15, 00:00 authored by Xingfei Wei, Tengfei LuoWater transport through carbon nanotubes
(CNTs) and boron nitride
nanotubes (BNNTs) has attracted great scientific interest because
of their potential applications in water purification and energy conversion.
Recent experiments show surprising differences of the water flow friction
coefficients in these two types of nanotubes with similar diameters,
but the mechanism is yet to be fully understood. We use molecular
dynamic simulations to model the transport process of water molecules
inside CNTs and BNNTs, and the friction coefficients are calculated
by the Green–Kubo formula. Our results show that at similar
diameters, water molecules have smaller friction coefficients in zigzag
CNTs than in zigzag BNNTs. By analyzing the potential energy landscape
inside these nanotubes, we find that in CNTs, the lack of partial
charges, and thus the absence of electrostatic interactions with water
molecules, leads to a much smoother potential energy landscape and
thus smaller water friction coefficient. Although partial charges
in armchair BNNTs also lead to electrostatic interactions with water,
the atomic arrangement in armchair nanotubes does not create local
potential energy traps, and thus the friction coefficient is smaller
than the zigzag counterparts. The result helps us understand the distinct
behaviors of water flowing through CNTs and BNNTs.