Related Experiment Video
Updated: Jun 14, 2026
14:52
Fabrication of Three-Dimensional Graphene-Based Polyhedrons via Origami-Like Self-Folding
Published on: September 23, 2018
9.0K
Solvent-Assisted Graphene Exfoliation from Graphite Using Umbrella Sampling Simulations
Anastasios Gotzias1, Elena Tocci2, Andreas Sapalidis1
1Institute of Nanoscience and Nanotechnology, NCSR Demokritos, Athens 153 10, Greece.
Langmuir : the ACS Journal of Surfaces and Colloids
|December 5, 2023
Summary
Non-water solvents like DMA, NMP, DMSO, and cyclohexane effectively exfoliate graphene layers from substrates. Parallel exfoliation is more favorable than perpendicular, with non-water solvents showing similar efficiency.
Area of Science:
- Materials Science
- Computational Chemistry
- Surface Science
Background:
- Graphene exfoliation is crucial for its applications.
- Understanding solvent effects on graphene exfoliation is key.
- Molecular dynamics simulations offer insights into nanoscale phenomena.
Purpose of the Study:
- To investigate the thermodynamics of single graphene layer exfoliation from a graphitic substrate.
- To compare the effectiveness of five different solvents (DMA, NMP, DMSO, CHX, water) in graphene exfoliation.
- To analyze the influence of exfoliation direction (parallel vs. perpendicular) on the process.
Main Methods:
- Employed molecular dynamics (MD) simulations.
- Utilized umbrella sampling to calculate free energies.
- Generated initial configurations using steered MD simulations.
- Modeled the substrate as a stack of three graphene layers.
Main Results:
- Uniform wetting behavior observed for graphene nanosheets and substrates in all tested solvents.
- Exfoliation is more thermodynamically favorable in the parallel direction compared to the perpendicular direction.
- Non-water solvents (DMA, NMP, DMSO, CHX) demonstrated comparable and effective graphene exfoliation.
- Calculated free energies for parallel exfoliation in non-water solvents ranged from 90-100 kJ/mol/nm².
- Perpendicular exfoliation yielded lower free energy values due to nonequilibrium effects and high steering velocity.
Conclusions:
- Non-water solvents are effective for graphene exfoliation, with similar efficiencies.
- The direction of exfoliation significantly impacts the thermodynamics.
- Nonequilibrium effects in perpendicular exfoliation lead to elevated system energy and heating.
Related Concept Videos
01:20Preparation of Samples for Electron Microscopy
To be visualized by an electron microscope, either transmission or scanning, biological samples need to be fixed (stabilized) so the electron beam does not destroy them and dried thoroughly (desiccated/dehydrated) so the vacuum does not affect them. Fixation needs to be done as quickly as possible because the sample properties will start changing as soon as it is removed from its natural environment. For example, in a tissue sample, the oxygen levels begin decreasing, causing an altered...
01:03Precipitation Gravimetry
Precipitation gravimetry is based on converting an analyte into a sparingly soluble precipitate, which is separated by filtration and weighed. An ideal precipitate should be pure, insoluble, of known composition, and easily filtered from the reaction mixture.
In determining nickel by gravimetric analysis, a precipitant of ethanolic dimethylglyoxime is added to a hot nickel salt solution. This is quickly followed by the dropwise addition of dilute ammonia solution until precipitation occurs. A...
In determining nickel by gravimetric analysis, a precipitant of ethanolic dimethylglyoxime is added to a hot nickel salt solution. This is quickly followed by the dropwise addition of dilute ammonia solution until precipitation occurs. A...
01:08Sample Preparation for Analysis: Advanced Techniques
Accurate analysis of complex samples often requires advanced preparation techniques to achieve reliable and reproducible results. Samples containing inorganic or organic materials can be challenging to dissolve or decompose effectively. Standard sample preparation methods include acid digestion, fusion, dry ashing, and wet digestion.
Acid digestion with strong acids is commonly used to dissolve inorganic materials that are insoluble (do not dissolve) in water. This method can be useful for...
Acid digestion with strong acids is commonly used to dissolve inorganic materials that are insoluble (do not dissolve) in water. This method can be useful for...