Carbon nanofluidic structures made of carbon nanotubes or graphene/graphene oxide have shown great promise in energy and environment applications due to the newly discovered fast and selective mass transport. However, they have yet to be utilized in nanofluidic devices for lab-on-a-chip applications because of great challenges in their fabrication and integration. Herein we report the fabrication of two-dimensional planar graphene nanochannel devices and the study of ion transport inside a graphene nanochannel array. A MEMS fabrication process that includes controlled nanochannel etching, graphene wet transfer, and vacuum anodic bonding is developed to fabricate graphene nanochannels where graphene conformally coats the channel surfaces. We observe higher ionic conductance inside the graphene nanochannels compared with silica nanochannels with the same geometries at low electrolyte concentrations (10 M-10 M). Enhanced electroosmotic flow due to the boundary slip at graphene surfaces is attributed to the measured higher conductance in the graphene nanochannels. Our results also suggest that the surface charge on the graphene surface, originating from the dissociation of oxygen-containing functional groups, is crucial to the enhanced electroosmotic flow inside the nanochannels.
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http://dx.doi.org/10.1039/c6nr06977k | DOI Listing |
Adv Mater
January 2025
School of Materials Science and Engineering, Beihang University, Beijing, 100191, China.
Small
January 2025
School of Physics, East China University of Science and Technology, Shanghai, 200237, China.
Water and ion transport in nanochannels is crucial for membrane-based technology in biological systems. 2D materials, especially graphene oxide (GO), the most frequently used as the starting material, are ideal building blocks for developing synthetic membranes. However, the selective exclusion of small ions while maintaining in a pressured filtration process remains a challenge for GO membranes.
View Article and Find Full Text PDFAdv Sci (Weinh)
December 2024
Institute for Frontier Materials, Deakin University, Geelong, Victoria, 3220, Australia.
Two-dimensional (2D) nanochannels have demonstrated outstanding performance for sieving specific molecules or ions, owing to their uniform molecular channel sizes and interlayer physical/chemical properties. However, controllably tuning nanochannel spaces with specific sizes and simultaneously achieving high mechanical strength remain the main challenges. In this work, the inter-sheet gallery d-spacing of graphene oxide (GO) membrane is successfully tailored with high mechanical strength via a general radical-induced polymerization strategy.
View Article and Find Full Text PDFNanoscale
December 2024
Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012, India.
Water-based nanofluidic devices, where water is confined in Angstrom scale nanochannels, are widely encountered in nanotechnology. Although it is known that the material of confinement has a significant influence on the properties of confined water, much less is known of the relationship between the structure of nanoconfined water and its properties, impacting the design of nanofluidic devices. We explore the behavior of a confined water monolayer within a bilayer molybdenum disulfide (MoS) structure, comparing its behavior with that within bilayer graphene.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
MIIT Key Laboratory of Semiconductor Microstructure and Quantum Sensing, and Department of Applied Physics, Nanjing University of Science and Technology, Nanjing 210094, China.
Water confined in two-dimensional channels exhibits unique properties, such as rich morphology, specific phase transition and a low dielectric constant. In this work, molecular dynamics simulations have been used to study the water transport in two-dimensional graphene channels. The structures and dynamics of water under confinement show strong dependence on the channel length and thickness of the channels.
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