|Manu||Date: Thursday, 25-November-2021, 10:32 PM | Message # 1|
|'Super jelly' can survive being run over by a car|
by University of Cambridge
Researchers have developed a jelly-like material that can withstand the equivalent of an elephant standing on it, and completely recover to its original shape, even though it's 80% water.
The soft-yet-strong material, developed by a team at the University of Cambridge, looks and feels like a squishy jelly, but acts like an ultra-hard, shatterproof glass when compressed, despite its high water content.
The non-water portion of the material is a network of polymers held together by reversible on/off interactions that control the material's mechanical properties. This is the first time that such significant resistance to compression has been incorporated into a soft material.
The 'super jelly' could be used for a wide range of potential applications, including soft robotics, bioelectronics or even as a cartilage replacement for biomedical use. The results are reported in the journal Nature Materials.
The way materials behave—whether they're soft or firm, brittle or strong—is dependent upon their molecular structure. Stretchy, rubber-like hydrogels have lots of interesting properties that make them a popular subject of research—such as their toughness and self-healing capabilities—but making hydrogels that can withstand being compressed without getting crushed is a challenge.
"In order to make materials with the mechanical properties we want, we use crosslinkers, where two molecules are joined through a chemical bond," said Dr. Zehuan Huang from the Yusuf Hamied Department of Chemistry, the study's first author. "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."
Working in the lab of Professor Oren Scherman, who led the research, the team used barrel-shaped molecules called cucurbiturils to make a hydrogel that can withstand compression. The cucurbituril is the crosslinking molecule which holds two guest molecules in its cavity—like a molecular handcuff. The researchers designed guest molecules that prefer to stay inside the cavity for longer than normal, which keeps the polymer network tightly linked, allowing for it to withstand compression.
Read more/full article/source - https://phys.org/news/2021-11-super-jelly-survive-car.html