Related Experiment Video
Updated: Jun 8, 2026
14:52
Fabrication of Three-Dimensional Graphene-Based Polyhedrons via Origami-Like Self-Folding
Published on: September 23, 2018
Irreversibility in response to forces acting on graphene sheets
N Abedpour1, Reza Asgari, M Reza Rahimi Tabar
1Department of Physics, Sharif University of Technology, 11365-9161, Tehran, Iran.
Physical Review Letters
|September 28, 2010
Summary
Researchers discovered an irreversible compression-relaxation mechanism that creates static ripples in suspended graphene sheets. This explains the common ripple structure and reveals a critical temperature (Tc) below which rippled graphene has lower free energy.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Graphene sheets exhibit ripples, influenced by substrate interactions or suspending structures.
- The origin of the ubiquitous ripple structure in suspended graphene has been a subject of investigation.
Purpose of the Study:
- To investigate the irreversibility in the mechanical response of suspended graphene sheets to applied forces.
- To elucidate the mechanism behind the formation of static ripples in graphene.
- To determine the critical temperature (Tc) at which rippled graphene becomes energetically favorable.
Main Methods:
- Applying controlled compression and relaxation forces to suspended graphene sheets.
- Observing and analyzing the resulting ripple structures.
- Thermodynamic analysis to compare the free energy of rippled versus roughened graphene states.
Main Results:
- An irreversible compression-relaxation mechanism was identified as the cause of static ripples.
- A critical temperature (Tc) was determined, below which the free energy of rippled graphene is lower than that of roughened graphene.
- The critical temperature (Tc) was found to be dependent on structural parameters and sample size.
Conclusions:
- The observed irreversibility in mechanical response explains the prevalence of ripple structures in suspended graphene.
- A specific temperature threshold (Tc) governs the energetic stability of rippled graphene configurations.
- Graphene's structural properties, including sample size, influence this critical temperature, offering insights for material design.
Related Concept Videos
01:14Reversible and Irreversible Processes
The thermodynamic processes can be classified into reversible and irreversible processes. The processes that can be restored to their initial state are called reversible processes. It is only possible if the process is in quasi-static equilibrium, i.e., it takes place in infinitesimally small steps, and the system remains at equilibrium However, these are ideal processes and do not occur naturally. An ideal system undergoing a reversible process is always in thermodynamic equilibrium within...
01:26Reversible or Opposing Reactions
Reversible or opposing reactions play a crucial role in understanding the dynamic nature of chemical processes. While kinetics focuses on how reactions proceed, thermodynamics emphasizes that most reactions do not reach completion. Instead, a reverse reaction starts occurring over time, and when its rate equals that of the forward reaction, a dynamic equilibrium is established.For example, consider a simple chemical process where A forms B reversibly. The rate constants for the forward and...
01:24Types of Reversible Electrodes
For electrode reversibility to be maintained, all the reactants and products involved in the half-reaction must be present at the electrode. There are several types of reversible electrodes (half-cells).In metal-metal-ion electrodes, a metal balances electrochemically with a solution of its own ions. Examples are Cu2+|Cu and Zn2+|Zn. Metals that react with the solvent, like group 1 and most group 2 metals, which react with water, and zinc, which reacts with aqueous acidic solutions, cannot be...
01:34Woodward–Hoffmann Selection Rules and Microscopic Reversibility
Electrocyclic reactions, cycloadditions, and sigmatropic rearrangements are concerted pericyclic reactions that proceed via a cyclic transition state. These reactions are stereospecific and regioselective. The stereochemistry of the products depends on the symmetry characteristics of the interacting orbitals and the reaction conditions. Accordingly, pericyclic reactions are classified as either symmetry-allowed or symmetry-forbidden. Woodward and Hoffmann presented the selection criteria for...
01:13Cell-matrix's Response to Mechanical Forces
In animal cells, the extracellular matrix allows cells within tissues to withstand external stresses and transmits signals from the outside of the cell to the inside. The extracellular matrix is extensive, and its composition varies between different types of tissues. For example, the reticular fibers and ground substance make up the ECM in loose connective tissue, while collagen and bone minerals make up the ECM of bone tissue.
Anchoring junctions mechanically attach a cell to the...
Anchoring junctions mechanically attach a cell to the...
01:08Types of Chemical Reactions: Exchange and Reversible
An exchange reaction is a chemical reaction in which both synthesis and decomposition occur, chemical bonds are both formed and broken, and chemical energy is absorbed, stored, and released.
A special kind of exchange reaction is the oxidation-reduction reaction, or the redox reaction. These reactions involve the transfer of electrons from one compound to another. The electrons in these reactions commonly come from hydrogen atoms, which consist of an electron and a proton. A molecule gives up a...
A special kind of exchange reaction is the oxidation-reduction reaction, or the redox reaction. These reactions involve the transfer of electrons from one compound to another. The electrons in these reactions commonly come from hydrogen atoms, which consist of an electron and a proton. A molecule gives up a...