Having plastic, paints, and coating that can repair itself would revolutionize technology, design, and sustainable production. Researchers have been working on this kind of material for a long time and now a team from Clemson University think they are only a few steps away from full-scale industrial production.
Plastics are made from long molecular chains called polymers stuck into place during the production process. Previous self-healing plastics have used more complex bonding approaches to bring the molecules back together after damage or required added reactants that come into play when there’s a break.
As reported in Science, the new work uses the natural intermolecular forces between the polymers to not only make them stronger but also help them reunite if they are separated due to damage. If the polymers are placed in the right way, these forces, known as van der Waals forces, act as a lock-and-key mechanism. The polymers are stuck together.
"At the same time, they like each other," lead author Professor Marek Urban said in a statement. "So, when you pull them out, they come back together. It becomes self-healable at that point. As simple as this may sound, these studies also revealed that ubiquitous and typically weak van der Waals interactions in plastics, when oriented, will result in self-healing. This discovery will impact the development of sustainable materials using weak bonding which becomes collectively very strong when oriented."
While the detailed science is intriguing, the key strength of this research is its simple approach. Producing polymer-based material like this would not require the development of a completely new line of production. It could be done in existing factories. The team estimate that increasing production to reach hundreds of gallons of polymers could be done in six months to a year.
"For anybody who wants to make these types of self-healing materials, they would have to essentially design a synthetic process and scale it up," Urban said. "The key is that the scale-up process would have to be precisely controlled. There is a huge difference between making something in the lab and scaling it up. We know the technology is available for them."