Page 79 - Read Online

Xing et al. Microstructures 2023;3:2023031 https://dx.doi.org/10.20517/microstructures.2023.11 Page 19 of 35

Figure 7. Regulating length of nanochannels. (A) side view of the computational system of ultrathin graphene membrane in the
[134]
desalination process . Copyright 2012, American Chemical Society. (B) The simulation box consists of a single-layer MoS sheet
2
[137]
(molybdenum in blue and sulfur in yellow), water (transparent blue), ions (in red and green), and a graphene sheet (in gray) .
Copyright 2015, Springer Nature. (C) The fabrication process of density pores on graphene-nanomesh/carbon-nanotube hybrid
[138]
membranes using O plasma . Copyright 2019, Science Publishing Group.
2

Figure 8. Regulating morphology of nanochannels: inter-edge gaps (A), intrinsic pores (B), and nanowrinkles (C).

inter-edge gaps and intrinsic pores, enabling nanofluids to take shortcuts to perform ultrafast transport. A
few works have developed simple methods for the lateral size fractionation of 2D nanosheets using
[141]
[142]
[140]
techniques such as sonication , filtrations , differential centrifugation , and controlled directional
freezing . It is found that when the dimension of nanosheets within the membrane is changed from
[143]
microsize to nanosize, the amount of nanofluidic pathways formed within the GO membrane is increased
significantly, resulting in the enhancement of trans-membrane transportation in the case of nanosized 2D-
material membranes . Nie et al. exploited this concept of lateral dimension control to engineer shorter
[144]
and less tortuous transport pathways for solvent molecules, leading to the development of small-flake GO
membranes that achieved ultrafast selective molecular transport . The methanol permeance in these
[145]
membranes reached up to 2.9-fold higher than its large-flake GO counterpart, with high selectivity towards
organic dyes . Section 2.2 has described various perforation techniques to produce nanopores on 2D
[145]