University of Otago, New Zealand

Chemistry

Te Tari Hua-Ruanuku

Starting to Gel: A Tough, Stretchy, Mouldable New Material

Thursday 26 March 2015

Chemists don’t usually drop balls from helicopters flying at 1200 feet, but Prof Lyall Hanton and his team from the University of Otago wanted to test a new material they have created by throwing it out the window.

The material they were testing is a gel, made mostly of water.  The balls, which could fit in the palm of your hand, not only survived the fall from the helicopter intact they also bounced when they hit the ground.

It’s a sign of how tough these gels are.

The gel is also incredibly stretchy, stretching at least 40 times, and will still bounce back to its original size after being compressed 99%.

The gel consists of 85% water, plus a monomer and a crosslinker. In the gel, the monomers form polymers, and the crosslinker binds the ends of these extremely long polymer chains in a three dimensional network.

The gels are cross-linked in such a way that the long, linked polymer chains can be stretched much more than short chains, resulting in the strong, stretchable gel.

The team are already thinking of many possible applications such as soft bandages, a high-tech shoe pad for running shoes or for use in a gel actuator.

Radio New Zealand National, Our Changing World, Thursday 26 March 2015