Unimpeded Permeation of Water Through Helium-Leak–Tight Graphene-Based Membranes

Abstract

Permeation through nanometer pores is important in the design of materials for filtration and separation techniques and because of unusual fundamental behavior arising at the molecular scale. We found that submicrometer-thick membranes made from graphene oxide can be completely impermeable to liquids, vapors, and gases, including helium, but these membranes allow unimpeded permeation of water (H(2)O permeates through the membranes at least 10(10) times faster than He). We attribute these seemingly incompatible observations to a low-friction flow of a monolayer of water through two-dimensional capillaries formed by closely spaced graphene sheets. Diffusion of other molecules is blocked by reversible narrowing of the capillaries in low humidity and/or by their clogging with water.

Electronics and optoelectronics of two-dimensional transition metal dichalcogenides

“…The electronic band structure of graphene has a linear dispersion near the K point, and charge carriers can be described as massless Dirac fermions, providing scientists with an abundance of new physics 2,3 . Graphene is a unique example of an extremely thin electrical and thermal conductor 4 , with high carrier mobility 5 , and surprising molecular barrier properties 6,7 .Many other 2D materials are known, such as the TMDCs 8,9 , transition metal oxides including titania-and perovskite-based oxides 10,11 , and graphene analogues such as boron nitride (BN) 12,13 . In particular, TMDCs show a wide range of electronic, optical, mechanical, chemical and thermal properties that have been studied by researchers for decades 9,14,15 .…”

“…The electronic band structure of graphene has a linear dispersion near the K point, and charge carriers can be described as massless Dirac fermions, providing scientists with an abundance of new physics 2,3 . Graphene is a unique example of an extremely thin electrical and thermal conductor 4 , with high carrier mobility 5 , and surprising molecular barrier properties 6,7 .…”

Friction of Water on Graphene and Hexagonal Boron Nitride from Ab Initio Methods: Very Different Slippage Despite Very Similar Interface Structures

“…This comes about because of the greater corrugation of the energy landscape on boron nitride arising from specific electronic structure effects. We discuss how a subtle dependence of the friction on the atomistic details of a surface, that is not related to its wetting properties, may have a significant impact on the transport of water at the nanoscale, with implications for the development of membranes for desalination and for osmotic power harvesting.Nanofluidics is an exciting field that offers alternative and sustainable solutions to problems relating to energy conversion, water filtration and desalination [1][2][3][4][5][6][7][8][9]. Miniaturization towards nanofluidic devices inevitably leads to an enhanced influence of surface and interface properties as opposed to those of the bulk.…”

Self-assembled two-dimensional nanofluidic proton channels with high thermal stability

“…These high aspect ratio 2D sheets, regardless of material composition, have a unique advantage over other morphologies in that they are the only shape that can stack to yield continuous interstitial space, which is both percolated throughout the material and highly uniform in size and orientation. This offers unprecedented opportunity to construct nanofluidic channels to study molecular transport [9][10][11][12] . The width of such lamellar channels is comparable to the apparent thickness of the 2D sheets, and typically can be adjusted from around half a nanometre to several nanometres.…”