The research group of Professor Kenichiro Koga of Okayama University Graduate School analyzed the behavior of water trapped inside carbon nanotubes by molecular simulation, and showed for the first time in the world that there is a solid-liquid critical point that makes it impossible to distinguish between solid and liquid. rice field.Of the three states of matter, the gas-liquid critical point that makes it impossible to distinguish between liquid and gas is already known, but the solid-liquid critical point has not been found for any substance.

From the press release

From the press release


Molecular simulation is a method of reproducing the movement of atoms and molecules in a substance by calculating the attractive and repulsive forces acting on each of the atoms that make up the substance with a computer.It is very useful for analyzing phenomena that are difficult to verify in experiments and for predicting phenomena prior to experiments.Professor Koga et al. Investigated how water molecules trapped in carbon nanotubes behave when pressure and temperature are changed in this way.As a result, it became clear that when a high pressure of 1000 to hundreds of thousands of atmospheres was applied, the behavior was such that it became impossible to distinguish between liquids and solids.It was the first discovery of evidence that a solid-liquid critical point exists in the world.

This discovery is based on computer simulation, but it seems likely that it can actually be observed.If this state can be realized by experiments, it is expected that it will be possible to develop chemical reactions that occur only under the conditions of the solid-liquid critical point.In addition, since it is predicted that the thermal conductivity of carbon nanotubes will change rapidly, it may be possible to control the thermal conductivity by using the change of state of the substance trapped inside.

Source:[Okayama University] Discovered the world's first solid-liquid critical point whose existence was denied. Molecular simulation of water in nanospace

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