International. A research team from Tohoku University, Nissan Motor Co., Shinshu University and Okayama University made a groundbreaking discovery in the quest to replace hydrofluorocarbons in cooling systems with natural refrigerants such as water and alcohol.
Their study included performing a phase transition from liquid to gas through a nanosponge, a soft, elastic material equipped with tiny nanopores smaller than 10 nanometers. Their findings could lead to more efficient refrigerants with a lower carbon footprint.
The team of researchers successfully carried out a phase transition from liquid to force-driven gas using a nanosponge. When a normal, damp sponge is squeezed, naturally, water is expected to come out. However, when using a nanosponge with a pore size of less than 10 nanometers, a different phenomenon occurs. Even under low pressure, the sponge retains its liquid.
However, when applying force, the expelled liquid immediately evaporates into gas. In addition, as the sponge returns to its natural shape, it re-adsorbs the gas as a liquid into the nanopores.
Until now, researchers have not carried out the compression process of nanoporous materials because conventional materials are too difficult to deform. However, the team avoided this by creating their own soft, elastic and nanoporous materials, which consist of a single layer of graphene walls. They measured their results using homemade equipment designed to monitor the liquid gas phase transition when mechanical force is applied.
The team thought about the compression method after developing soft nanoporous materials. But even they couldn't anticipate their prediction becoming reality on the first try.
To date, there have been only two methods of converting the trapped liquid into gas: heating or decreasing the pressure of the gas phase. The compression method provides a third way, generating a new topic in the field of physical chemistry and paving the way for more environmentally friendly refrigeration systems.
Source: https://www.sciencedaily.com/releases/2019/06/190619094852.htm
