Polymers that get smaller when stretched may be key to plastic that heals itself.
A CHEMISTRY team in the US may have found the key to producing a plastic that can heal itself.
Graduate student Jeremy Lenhardt was testing the limits of polymers - molecules that form the basis for materials in our daily lives such as silicon, rubber and neoprene - in the chemistry lab at Duke University in North Carolina.
Working his way through a "library" of polymers, Mr Lenhardt stumbled across one particular species that reacted bizarrely.
The polymers contained ring-shaped molecules called gem-difluorocyclopropanes, which, when stretched, remained in that state for much longer than expected, before shrinking back to even smaller rings.
Yes, the more they were stretched, the smaller they got.
"To come across this discovery was a bit like having Christmas in July. And then August. And then September," Mr Lenhardt said."I ran up to (collleague Stephen Craig's) office (and said) 'Steve, something funny is going on here. Look at this!'"
Which is all well and good if you've got a chemistry degree and understand the importance of "transition states", but all that comes later.
For now, the important question is - will we ever suffer from flat tyres again?
What about mid-air explosions on planes? Will the hole disappear before we even see it?
Military applications?
Mr Craig said it was far too early to predict how the discovery would impact on our daily lives and was "reluctant to speculate" - but he did anyway."Imagine that when small holes are formed in a piece of stretched plastic, the molecules in the plastic around it have gone into this "overstretched" state, so that once the stretching is over, they pull back even closer than before and help to mend the hole," he told NEWS.com.au.
"Behaviour like this could be one piece (out of many) that could help to make something like that happen."
He described the polymers' behaviour as akin to what happens to a rope during a tug-of-war.
The rope is stretched and inside the rope, some of the strands break.
When the game's over, the threads that are broken find each other and reform in a different way to which they are formed, actually pulling the rope into a shorter length.
For all the chemists out there, it's the length of the transition state in the polymers that causes the most excitement, because it's by studying these that they can understand how products are formed from chemical reactions.
It's the key to converting one type of substance into another, such as in the creation of a new drug or material.
Normally, transition states occur in less than a tenth of a millionth of a millionth of second - far too quickly to study.
The polymers that Mr Lenhardt studied held their transition states for much, much longer, Mr Craig said, opening up the possibility of forming entirely new materials in a crisis.
"Perhaps these transition states that are trapped might be induced to form new bonds in a plastic right before it rips catastrophically," he said.
"Maybe the greatest contribution of this work is that it opens up new possibilities to consider.
"I suspect that whatever impact Jeremy's discovery has on future applications, it is most likely to be as a part of something that we haven't considered yet."