Two new types of revolutionary materials.

Article 1 : by Tia Ghose

Ultralight 'Super-Material' Is 10 Times Stronger Than Steel

A spongy new super-material could be lighter than the flimsiest plastic yet 10 times stronger than steel.

The new super-material is made up of flecks of graphene squished and fused together into a vast, cobwebby network. The fluffy structure, which looks a bit like a psychedelic sea creature, is almost completely hollow; its density is just 5 percent that of ordinary graphene, the researchers said.

What's more, though the researchers used graphene, the seemingly magical properties of the material do not totally depend on the atoms used: The secret ingredient is the way those atoms are aligned, the scientists said.

"You can replace the material itself with anything," Markus J. Buehler, a materials scientist at the Massachusetts Institute of Technology (MIT) said in a statement. "The geometry is the dominant factor. It's something that has the potential to transfer to many things."

Graphene, a material made up of flaky sheets of carbon atoms, is the strongest material on Earth — at least in 2D sheets. On paper, ultrathin sheets of graphene, which are just an atom thick, have unique electrical properties and indomitable strength. Unfortunately, these properties don't easily translate to 3D shapes that are used to build things. 

Past simulations suggested that orienting the graphene atoms a specific way could enhance strength in three dimensions. However, when researchers tried to create these materials in the lab, the results were often hundreds or thousands of times weaker than predicted, the researchers said in the statement. 

Stronger than steel

To address this challenge, the team got down to basics: analyzing the structure at the atomic level. From there, the researchers created a mathematical model that can accurately predict how to create remarkably strong super-materials. The researchers then used precise amounts of heat and pressure to produce the resulting curvy, labyrinthine structures, known as gyroids, which were first mathematically described by a NASA scientist in 1970.

"Actually making them using conventional manufacturing methods is probably impossible," Buehler said.

The material's strength comes from its enormous surface-area-to-volume ratio, the researchers reported in a study published Jan. 6 in the journal Science Advances. In nature, sea creatures like coral and diatoms also leverage a large surface-area-to-volume ratio to achieve incredible strength at tiny scales.

"Once we created these 3D structures, we wanted to see what's the limit — what's the strongest possible material we can produce," study co-author Zhao Qin, a civil and environmental engineering researcher at MIT, said in the statement.

The scientists created a series of models, built them, and then subjected them to tension and compression. The strongest material the researchers created was about as dense as the lightest plastic bag, yet stronger than steel.

One obstacle to creating these superstrong materials is the lack of industrial manufacturing capability for producing them, the researchers said. However, there are ways the material could be produced at larger scales, the scientists said

For instance, the actual particles could be used as templates that are coated with graphene through chemical vapor deposition; the underlying template could then be eaten or peeled away using chemicals or physical techniques, leaving the graphene gyroid behind, the researchers said.

In the future, massive bridges could be made of gyroid concrete, which would be ultrastrong, lightweight, and insulated against heat and cold because of all the myriad air pockets in the material, the researchers said.

Article 2 : by Tia Ghose 

Strong, Flexible Spider Silk Created in Lab

We've built skyscrapers, planes that travel faster than sound and particle colliders a mile below the Earth's surface.

Yet in some ways, the humble little house spider has got humans beat: The silken threads spiders use to ensnare prey are amazing feats of natural engineering. Pound-for-pound, inch-for-inch, spider silk can absorb huge amounts of energy without ripping apart. It's stronger than steel, yet springier than rubber.

Now, scientists have created a synthetic spider silk with many of the same properties as its wild counterpart, and they can produce it on a large scale — overcoming two limitations that have stymied past research in the area.

Tough and stretchy

The hunt for a natural mimic to spider silk is nothing new. For instance, in 2010 the National Science Foundation funded a project to genetically engineer goats to produce spider silk in their milk, while other projects focused on mass-producing spider silk proteins, called "spidroins," in yeast, bacteria and insect cells. In 2015, researchers reported in the journal Biomaterials that they had used spidroins produced by transgenic goats to form scaffolding for growing brain cells.

"Since spiders are territorial and produce small amounts of silk, any industrial application of spider silk requires production of recombinant spidroins and generation of artificial spider silk fibers," the researchers wrote in a paper published Monday (Jan. 9) in the journal Nature Chemical Biology.

However, previously engineered spidroins weren't replicas of those found in wild arachnids. The engineered silk proteins produced in solutions could be produced in disappointingly small quantities at low concentrations; they would clump together; and they didn't stay dissolved in liquids, the researchers reported.

What's more, those ersatz spider silk threads that were produced had lackluster physical properties unless they were treated extensively after initial creation, the researchers wrote.

It turns out that spiders naturally produce silk in silk-spinning ducts, and that the pH (how acidic a substance is) along that gland gradually varied from about 7.6 (slightly basic, meaning there were more negatively charged ions present) to less than 5.7 (acidic, meaning there were more positively charged ions present). This shift in pH pushes the proteins to change shape at their ends, causing the proteins to self-assemble like a lock-and-trigger, according to a 2014 study in the journal PLOS Biology. At the same time, the duct, which at the top looks a bit like a slightly less-wrinkled brain, narrows into a thin tube, and the sheer force of going through the tube pulls the fibers into strands, the researchers found.

Mimicking spider ducts

The team wondered whether mimicking the conditions in the spider's own silk glands might produce better results. They also noticed that portions of naturally occurring spider silk proteins from different species of spiders had a different pH and ability to dissolve.

So, the researchers combined spidroin genes from two spider species to create a hybrid spider silk gene called NT2RepCT. The NT2RepCT coded for a completely new protein that combined the best properties from the spidroins of the two species: high solubility and high sensitivity to pH. They then inserted the gene for the hybrid silk protein into the DNA of bacteria, which produced the proteins.  

In the end, this process produced a highly concentrated solution of spider silk proteins that looked cloudy and viscous, just as real spider silk proteins do inside the silk glands. They then pumped this solution through a thin glass capillary, which mimicked the shearing that produced spider silk fiber in the real world, the researchers wrote in the paper. This process produced 3,280 feet (1,000 meters) of fiber in a 0.26 gallon (1 liter) flask, the researchers reported.

"The as-spun NT2RepCT fibers had a qualitatively similar stress-strain behavior to native spider silk in that they displayed an initial elastic phase up until a yielding point," after which the silk began to deform, the researchers wrote in the paper.

Also, while the synthetic spider silk acted much like the real thing, it had lower toughness and tensile strength than its natural counterpart, meaning it breaks more easily.

"One possible way to increase the toughness could be to spin NT2RepCT fibers with diameters closer to that of native dragline silk, as this apparently has an impact on the mechanical properties of silk fibers," the researchers wrote.

Resume :

My first article speak about of the "super-material". The "super-material" is a new material incredibly lightweight, but as much resistant that steel. This new material is constitute of graphene. But the property of graphene does not allow to make this "super-material". According to the scientists, the secret ingredient is the way how the atoms are aligned. Furthermore, this new material more strong that steel depend of it's geometric constitution to enable it to its resistance. 

My second article speak about the spider silk created in lab, the scientists have developed a spider silk synthesized who have as feature to be very resistant, more strong than steel, yet springier than rubber. Furthermore, this spider silk can produce it on a large scale. 

To conclude, this two news materials more stronger than steel, will change in the near future, the materials which is used like the steel for example.