A new supramolecular plastic that can self heal in an instant, and is easier to decompose and reuse
A research group led by Li Jianwei, senior researcher of medicity research laboratory in Finland, has explored a new material called supramolecular plastic, which will replace traditional polymer plastics with an environmentally friendly material that promotes sustainable development. The supramolecular plastics made by researchers using the liquid-liquid phase separation method have similar mechanical properties to traditional polymers, but the new plastics are easier to decompose and reuse.
Plastic is one of the most important materials in modern times. After a century of development, it has been integrated into all aspects of human life. However, the traditional polymer plastics have poor degradation and regeneration ability in nature, which has become one of the greatest threats to human survival. This situation is caused by the strong force inherent in the covalent bond connecting the monomers to form the polymer.
In order to meet this challenge, scientists suggest making polymers connected by non covalent bonds that are less powerful than covalent bonds. Unfortunately, weak interactions are often insufficient to keep molecules in materials with macroscopic dimensions, which hinders the practical application of non covalent materials.
Li Jianwei's research group at the University of Turku in Finland found that a physical concept called liquid-liquid phase separation (LLPs) can isolate and concentrate solutes, enhance the binding force between molecules, and promote the formation of macro materials. The mechanical properties of the obtained materials are comparable to those of conventional polymers.
Moreover, once the material is broken, the fragments can instantly reunite and heal themselves. In addition, when encapsulating a saturated amount of water, the material is an adhesive. For example, a joint sample made of steel can withstand a weight of 16 kg for more than one month.
Finally, the material is degradable and highly recyclable due to the dynamic and reversible nature of non covalent interactions.
"Compared with traditional plastics, our new supramolecular plastics are more intelligent, because they not only retain strong mechanical properties, but also retain dynamic and reversible properties, making the materials self-healing and reusable," explained Dr. Yu Jingjing, a postdoctoral researcher.
"A small molecule that produces supramolecular plastics was previously screened out from a complex chemical system. It forms an intelligent hydrogel material with magnesium metal cations. This time, we are very happy to use LLPs to teach the new skills of this old molecule," said Dr. Li Jianwei, chief researcher of the laboratory.
"Emerging evidence shows that LLPs may be an important process in the formation of cell compartments. Now, we have advanced this phenomenon inspired by biology and physics to meet the great challenges faced by our environment. I believe that more interesting material LLPs processes will be explored in the near future," Li continued.