8 Crossings, 192 atoms in tightest knot ever – Hydrogen turned into metal.
Knots are useful in everyday life – and the same is true on the molecular level, where braided or knotted strings of atoms and molecules can be put together in different patterns with varying characteristic.
Everyone knows that Kevlar very strong – impenetrable even to a bullet. But why? Its molecules connect to form long chains that run parallel to each other. Together these molecules form an extremely strong yet flexible material.
But the structure of Kevlar is relatively simple: identical molecules packed tightly next to each other like pencils in a pencil box. Knotted or woven strands of molecules, on the other hand, can potentially create an even more flexible, lighter and stronger material — a tightly knit sweater on the molecular level.
To create their stronger knot, a team of researchers mixed oxygen, nitrogen and carbon in a solution with metal ions. The organic molecules wrap themselves around sticky iron ions and chloride ions, crossing in just the right ways and at just the right points. The loose ends were then sealed together chemically, forming a completely tied knot with eight crossings. The number of crossings made the knot much tighter than anything that had ever been achieved before at the molecular level.
The Magic ingredient
There’s a very good reason for using natural rubber in heavy-duty tyres. The material don’t contain the proteins and phospholipids that give natural rubber its reinforcement. Nor do they experience the strain induced crystallization process that helps to improve the tensile strength of natural rubber. And all this becomes rather important when the tyre has to support a 40-ton truck or an airliner coming in to land.
So far, it’s proved virtually impossible to pair high-strength natural rubber with low rolling resistance, silica-based fillers, but there’s concerted effort.
The first successful silica-silane system to be developed for truck tyres could be a very big success story. The problem is it’s very difficult. Natural rubber contains a lot of proteins and phospholipids, which are highly polar molecules. This means they compete with the silane that’s traditionally used as a coupling agent to pair synthetic rubber to silica. Natural rubber lacks the vinyl and trans-double bonds that help its synthetic equivalent to form a strong link with the fillers materials. When you are using 20 – 30% epoxidation you can create a quite good interaction to the silica, but still need to use a small amount of silane. The best option is tetrasulfane silane, known as Si-69. There’s no direct alternative to using silane, but one option is to use pre-hydrophobized silica inside the natural rubber. In the case of the first passenger cars to use silica, this reduced the wet braking distance by around 7%. Of the “Magic Triangle” of tyre properties, that leaves wear resistance. It is unlikely to benefit directly from the introduction of silica, but the hope is that current levels of abrasion resistance could be maintained.
Hydrogen turned into metal in stunning act of alchemy that could revolutionize technology and spaceflight
For nearly 100 years, scientists have dreamed of turning the lightest of all the elements, hydrogen, into a metal.
Now, in a stunning act of modern-day alchemy, scientists at Harvard University have finally succeeded in creating a tiny amount of what is the rarest, and possibly most valuable, material on the planet, they reported in the journal Science.
Update: Physicists might have made a mistake in claiming to have turned hydrogen into a metal, experts say
For metallic hydrogen could theoretically revolutionize technology, enabling the creation of super-fast computers, high-speed levitating trains and ultra-efficient vehicles and dramatically improving almost anything involving electricity.
And it could also allow humanity to explore outer space as never before.
But the prospect of this bright future could be at risk if the scientists’ next step – to establish whether the metal is stable at normal pressures and temperatures – fails to go as hoped.
Professor Isaac Silvera, who made the breakthrough with Dr. Ranga Dias, said: “This is the holy grail of high-pressure physics.
“It’s the first-ever sample of metallic hydrogen on Earth, so when you’re looking at it, you’re looking at something that’s never existed before.”
At the moment the tiny piece of metal can only be seen through two diamonds that were used to crush liquid hydrogen at a temperature far below freezing. The amount of pressure needed was immense – more than is found at the center of the Earth.
Courtesy: Elastomers Technology Development Society (ETDS)