Researchers have developed a reversible, vapor-controlled system capable of toggling the physical and optical traits of advanced fluids on demand.

Led by Nagoya University and Kyoto University in Japan, the study demonstrates a method to control the optical and physical properties of materials from the molecular level to the macroscopic scale.

At the core of the development is host–guest chemistry. It is a process where two distinct molecules lock together purely through physical forces, completely avoiding permanent chemical bonds.