Scientists develop ‘super jelly’ that can withstand being run over by car

By Gwyn Wright via SWNS

A new ‘super jelly’ that can survive being run over by a car has been developed by scientists.

The squidgy substance can also withstand the equivalent of an elephant standing on it and recover to its original shape.

The soft-but-strong material, developed by scientists at the University of Cambridge, looks and feels like a squishy jelly but acts like a very hard, shatterproof glass when compressed- despite being 80 percent water.

It could be used in soft robotics and bioelectronics- and could even replace damaged cartilage in our bodies.

How materials behave- such as whether they are soft or hard, brittle or strong- depends on the way their molecules are structured.

Making hydrogels such as this one that can hold together when they are compressed is very challenging, the researchers said.

The part that is not water consists of a network of polymers, held together with on-off interactions that control its mechanical properties.

They used barrel-shaped molecules which hold two other types of molecule in a cavity, like a handcuff, to create the gel.

They chose molecules that stay inside the cavity for longer than normal, which kept all the polymers tightly knit together and allowed it to stay together when compressed.

When they changed the molecules in the cavity, the type of hydrogel they produced would change.

The researchers used the material to create a hydrogel pressure sensor that can monitor human motions- such as standing, walking and jumping- in real time.

“At 80 percent water content, you would think it would burst apart like a water balloon, but it doesn’t- it stays intact and withstands huge compressive forces," saidlead study author professor Oren Scherman

“The properties of the hydrogel are seemingly at odds with each other.

“People have spent years making rubber-like hydrogels, but that is just half of the picture.

“We have revisited traditional polymer physics and created a new class of materials that span the whole range of material properties ranging from rubber-like to glass-like states."

The study’s first author Dr. Zehuan Huang said: “In order to make materials with the mechanical properties we want, we use crosslinkers, where two molecules are joined through a chemical bond.

“We use reversible crosslinkers to make soft and stretchy hydrogels, but making a hard and compressible hydrogel is difficult and designing a material with these properties is completely counterintuitive.

“To the best of our knowledge, this is the first time that glass-like hydrogels have been made. We’re not just writing something new into the textbooks, which is really exciting, but we’re opening a new chapter in the area of high-performance soft materials.”

Study co-author Dr. Jade McCune said: “The way the hydrogel can withstand compression was surprising, it wasn’t like anything we’ve seen in hydrogels.

“We also found the compressive strength could be easily controlled through simply changing the chemical structure of the guest molecule inside the handcuff.”

The findings were published in the journal Nature Materials.

The research was funded in part by the Leverhulme Trust and a Marie Skłodowska-Curie Fellowship.