American researchers have developed a photosensitive material that hardens under the action of ultraviolet light and becomes ten times softer when exposed to green light, and can be changed back and forth multiple times. This ability to change makes it possible for new materials to be used as special coatings in the future, but it is still far from practical.

The Massachusetts Institute of Technology recently issued a press release saying that the new material that the researchers participated in was a "polymer metal-organic cage". The basic unit is a cage molecule containing metal atoms, which is "snap" from the polymer. Connected. This material can be changed between two different states, soft and hard. It is expected to be used as a coating for "self-healing" for automobiles, satellites, robots, etc.

The research team published a paper in the British journal Nature , adding that they add a light-sensitive molecule to the junction of the polymer and the metal atom. The change of the molecule affects the connection and changes the overall structure of the material.

Under ultraviolet irradiation, the atoms in the material will form relatively large clusters, making the material harder; the green light will change the photosensitive molecules, resulting in smaller clusters and softer materials, and the process takes about 5 hours. In the experiment, the new material can withstand up to 7 changes back and forth.

According to reports, this soft and hard "switching" feature brings "self-healing" ability to new materials. For example, cracks generated in a hard state can be self-repaired by softening and recombining the material in a soft state.

But the researchers say the results are far from practical, and one of the problems to be solved is that the metals used in the new materials are expensive palladium, and they hope to find cheap alternatives with the same performance to reduce costs.

(Source: Xinhua News Agency)