Mobility gradients yield rubbery surfaces on top of polymer glasses

Polymeric glasses have rubber-like surfaces

23 December 2021

Some polymeric glasses can have surface layers that are more rubber-like than glassy in behaviour, making them promising as ultra-stable glasses for TV screens and phone displays.

Many glassy materials have an ultrathin outer layer with quite different properties to the bulk of the material, being liquid and highly mobile rather than glassy in nature. In glassy materials made from polymers, this behaviour can be complicated due to polymer chains at the surface being entangled with polymer chains deeper in the material.

Now, a team that included two Kyushu University researchers has shown that this polymeric entanglement leads to transient rubbery properties at the surface of polymeric glasses.

Using a combination of theoretical and experimental studies, the team found that this property was displayed even by glasses made from short polymer chains that have less entanglement.

The discovery may have implications for devices that rely on the properties of the polymeric glass surface.

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References

1. Nature 596, 372–376 (2021). doi: 10.1038/s41586-021-03733-7