Making an Impression... or Not

Every few years, scientists come up with a wacky new material with properties that defy all sense. As a case in point just look at the eerie ferro-fluids – liquids that respond to magnetic fields; or aerogels that can support the weight of a brick but weigh only 2 grams. Well, the latest ‘fad’ (if you can call it that) in ‘out-there’ science projects is a little something called a hydrogel. Hydrogels have been around since the sixties, but are more recently coming into their own in the bio-medical sciences. They hold a variety of potentially useful properties including the ability to self-heal and can be made from a range of polymers. But you’ve yet to see the most astonishing thing of all.

I should say first of all that we’ve seen plenty of impact tests. Our drop-towers will rip through many common household and industrial materials. But I was surprised to see this video. Ordinarily, testing a film (in plastics testing, any polymeric material less than 1mm thick is a film) is a somewhat delicate operation.

But not with this mysterious concoction of compounds, which can absorb impacts of 9,000 joules per square meter and stretch up to 20 times its original length without breaking. Just to give you some perspective – if a bag of sugar weighed 1 kg, and you had just a square meter of this hydrogel – you could drop the bag of sugar onto the hydrogel from nearly a kilometre above and not penetrate it.

We’ve already seen hydrogels performing well in a variety of applications including contact lenses, tissue engineering and nappies (of all things!), but until now their lack of sufficient mechanical properties limited their versatility for widespread use. But with recent developments producing promising results, the future is looking bright for hydrogels.