Carbon Nanotubes and Nanofluidic Transport

Abstract

Recent strides have been made in both the modeling and measurement of fluid flow on the nanoscale. Carbon nanotubes, with their atomic dimensions and atomic smoothness, are ideal materials for studying such flows. This Progress Report describes recent modeling and experimental advances concerning fluid transport in carbon nanotubes. The varied flow characteristics predicted by molecular dynamics are described, as are the roles of defects and chirality on transport. Analytical models are increasingly being used to describe nanofluidic transport by relaxing many of the assumptions commonly used to describe bulk water. Recent experimental studies examine the size dependence of flow enhancements through carbon nanotubes and use varied spectroscopies to probe water structure and dynamics in these systems. Carbon nanotubes are finding increasing applications in biology, from protein filters to platforms for cell interrogation.

Vibrating carbon nanotubes as water pumps

“…1(a)), consistent with previous studies [26] and similar to the water chains inside the biological water channel aquaporins [27,28]. This water arrangement has been suggested to be largely responsible for the rapid water transport inside CNTs [29]. …”

“…A continuous hydrogen-bonded water chain has been suggested to be critical for water transport in nanochannels such as biological aquaporins and CNTs [26][27][28][29]. Can the continuity of a water chain still exist inside a vibrating CNT channel?…”

Carbon nanotube-based membranes: Fabrication and application to desalination

“…Thus, it is necessary to introduce a plausible transport phenomenon called ''nanofluidics''. In this novel theory, it is assumed that the fluid flowing through a nano-channel has a slip length with no friction [27]. Adopting the slip-flow condition, the Hagen-Poiseuille equation can be used as follows [26]:…”

High heat flux phase change on porous carbon nanotube structures

“…Likewise, investigations of the bulk CNT forests also show large variations in effective thermal conductivity ranging from 0.7 to 262 W/m K [9][10][11]. Permeability studies have focused on mass transfer along the longitudinal direction of CNTs for membrane development [12][13]. However, the in-plane permeability of the bulk CNT forests has not been reported.…”

“…The low permeability and thus the liquid transport limitation of the monoporous CNT forest traggered the development of bi-porous structures [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Conceptually, bi-porous structure has two different pore sizes.…”