The MIT learned to control plastic properties

For over a hundred years of plastic products and plastics are widely used in many areas of our lives. However, the physical properties of the material may depend not only on the composition but also on the molecular structure. Recently, engineers Massachusetts Institute of Technology (MIT) have created a metal-organic polymer, which can change its shape when exposed to light waves of varying lengths.

The MIT learned to control plastic properties

According to the editors of the journal Nature, the new material is created by a team led Yuveya Gu. The new metal-organic polymer hardens when exposed to ultraviolet light and becomes soft and fusible under green light. The change of physical properties occurs due to changes in the plastic particles. They are composed of chains of molecular ligands related to the palladium atoms. Such compounds are called metal-organic polymer due to the fact that the polymer have long "tails" which gather around the metal atoms forming the geometric structures in the form of quadrilaterals.

The new material every palladium atom forms a 4 chemical bonds with ligands. At the moment when accumulates many palladium and polymer molecules - in the structure formed with a variable number of clusters of metal atoms. Scientists have found a way to create "large" clusters of 24 atoms of palladium by 48 ligands and "small" - 3 of palladium atom in the 6 ligands. For transition control between clusters, researchers added DTE substance in the molecule which bond between two sulfur atoms is formed and breaks under ultraviolet light. The ultraviolet radiation DTE molecule becomes more rigid and severs small clusters, causing the palladium to form larger clusters. The reverse process occurs when exposed to green light bond in the molecule is destroyed DTE, which reduces the intensity of the impact and create small clusters. It turned out that the "small" clusters make the material very soft and fusible, which allows, for example, to repair mechanical damage. "Large" is cause hardening. At the same time we can produce up to 7 state change cycles, which does not affect the properties of the material, however, this figure is projected to increase in the future. It is not difficult to guess that this type of plastic is perfect for making things with longer life and for recycling.