Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog

Category: materials – Page 175

Synthetic spider silk stronger and tougher than the real thing

Year 2021 face_with_colon_three

Spider silk is one of nature’s most impressive materials, exhibiting impressive strength and toughness. Now, researchers at Washington University in St. Louis claim to have created an artificial version that can outperform some natural spider silks.

This isn’t the first rodeo for this research team – back in 2018 they developed a synthetic spider silk that was about on par with the real thing, in terms of tensile strength, extensibility and toughness. To do so, they spliced silk-producing genes into bacteria, and tweaked them so that proteins in the silk would fuse together to make a stronger, tougher material.

For the new study, the team built on this prior work to not just match natural spider silk but to surpass it. The key component is beta-nanocrystals, which boost the material’s strength but are hard to reproduce synthetically.

Chemists make the unimaginable possible in crystalline materials discovery

The world’s best artists can take a handful of differently colored paints and create a museum-worthy canvas that looks like nothing else. They do so by drawing upon inspiration, knowledge of what’s been done in the past and design rules they learned after years in the studio.

Chemists work in a similar way when inventing new compounds. Researchers at the U.S. Department of Energy’s (DOE) Argonne National Laboratory, Northwestern University and The University of Chicago have developed a new method for discovering and making new with two or more elements.

“We expect that our work will prove extremely valuable to the chemistry, materials and condensed matter communities for synthesizing new and currently unpredictable materials with exotic properties,” said Mercouri Kanatzidis, a chemistry professor at Northwestern with a joint appointment at Argonne.

The Donnan potential, revealed at last

The Donnan electric potential arises from an imbalance of charges at the interface of a charged membrane and a liquid, and for more than a century it has stubbornly eluded direct measurement. Many researchers have even written off such a measurement as impossible.

But that era, at last, has ended. With a tool that’s conventionally used to probe the chemical composition of materials, scientists at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) recently led the first direct measurement of the Donnan potential.

“We were naïve enough to believe we could do the impossible,” said Ethan Crumlin, a staff scientist at Berkeley Lab’s Advanced Light Source (ALS), which generated the bright X-rays used in the experiment. Crumlin and his collaborators recently reported the measurement in Nature Communications.

Study observes Luttinger liquid behavior in a quasi-2D system

Luttinger liquids are usually paramagnetic materials exhibiting non-Fermi liquid behavior, such as molybdenum oxides. These “liquids” and their fascinating properties had so far been only observed in 1D and quasi-1D compounds, such as blue bronze A0.3 MoO3 (A= K, Rb, Tl) and purple bronze Li0.9 Mo6O17.

Researchers at Tsinghua University, ShanghaiTech University, and other institutes in China recently observed prototypical Luttinger liquid behavior in η-Mo4O11,a charge-density wave material with a quasi-2D . Their findings, published in Nature Physics, could pave the way for the exploration of non-Fermi liquid behavior in other 2D and 3D quantum materials.

“In our previous work, we identified the Luttinger liquid phase in the normal state of blue bronzes, which is not surprising due to its quasi-1D nature,” Lexian Yang and Yulin Chen, two of the researchers who carried out the study, told Phys.org.

Scientists’ use of hydrogel materials leads to stem cells developing like human embryos

Materials scientists at UNSW Sydney have shown that human pluripotent stem cells in a lab can initiate a process resembling the gastrulation phase—where cells begin differentiating into new cell types—much earlier than occurs in mother nature.

For an embryo developing in the womb, occurs at day 14. But in a dish in a lab at UNSW’s Kensington campus, Scientia Associate Professor Kris Kilian oversaw an experiment where a gastrulation-like event was triggered within two days of culturing in a unique biomaterial that, as it turned out, set the conditions to mimic this stage of embryo development.

“Gastrulation is the key step that leads to the human body plan,” says A/Prof. Kilian.

Cooking with Phason Gas

Heat-transport measurements and neutron-scattering spectroscopy probe a form of thermal conduction based on excitations called phasons.

The understanding of how substances conduct heat is of great significance in materials science. It is needed for many important technological applications—from heat management in electronics to temperature control in buildings [1]. Therefore, when an unusual form of thermal transport is identified, materials scientists take notice. Michael Manley of Oak Ridge National Laboratory, Tennessee, and his colleagues have shown that excitations called phasons can provide the main contribution to thermal transport in a material known as fresnoite [2]. Phasons are collective lattice oscillations that occur in certain crystals with an aperiodic lattice structure—fresnoite being one of the best known. The researchers’ demonstration could pave the way for new heat-management strategies.

Thermal conductivity is a measure of a material’s ability to transfer heat. It is a property that we are all abruptly reminded of when we accidentally place our hand on a hot kitchen stove. The temperature gradient between our cooler skin and the hotter surface facilitates a transfer of energy into our hand, resulting in an unpleasant sensation. The notion that different materials conduct heat at different rates is similarly experienced when we perceive the cooling sensation of holding a metal spoon relative to a wooden one.

/* */