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A research team from Skoltech, Aalto University, and Kurnakov Institute has recently developed a new, versatile and simple approach to using carbon nanotubes for manufacturing carbon nanotube-polymer nanocomposites. The method is reported in Carbon and involves making briquettes—dense packages of carbon nanotube powders. Nanocomposites made with briquettes perform equally well as those made from the more expensive masterbatches, which are also polymer-specific—that is, less versatile.

“We believe the use of dense briquettes of carbon nanotubes can significantly facilitate the development of the carbon nanotube composite industry. This technique is cheap and applicable to a broad variety of polymer matrices, without sacrificing any of the electrical and thermal properties of the final material,” the lead author of the study, Skoltech Ph.D. student Hassaan Butt, stated.

Carbon nanotubes have been intensively investigated for decades by researchers from academia and industry because of their unique combination of electrical, thermal, and mechanical properties. Meanwhile, polymer-based nanocomposites have come to be the largest carbon nanotube application and the one closest to widespread integration into everyday life. It is easy to understand why: The smallest amounts of nanotubes added to a polymer endow the material with fundamentally new properties, such as electrical conductivity and piezoresistivity, as well as crucially enhancing its thermal and mechanical properties.

Lawrence Livermore National Laboratory (LLNL) scientists are scaling up the production of vertically aligned single-walled carbon nanotubes (SWCNT) that could revolutionize diverse commercial products ranging from rechargeable batteries, automotive parts and sporting goods to boat hulls and water filters. The research appears in the journal Carbon.

Most CNT production today is used in bulk composite materials and thin films, which rely on unorganized CNT architectures. For many uses, organized CNT architectures such as vertically aligned forests provide important advantages for exploiting the properties of individual CNTs in macroscopic systems.

“Robust synthesis of vertically-aligned carbon nanotubes at large scale is required to accelerate deployment of numerous cutting-edge devices to emerging commercial applications,” said LLNL scientist and lead author Francesco Fornasiero. “To address this need, we demonstrated that the structural characteristics of single-walled CNTs produced at wafer scale in a growth regime dominated by bulk diffusion of the gaseous carbon precursor are remarkably invariant over a broad range of process conditions.”

This is number 22 on IE’s list of 22 best innovations, a look back at recycling for all plastics.

Two companies, Plastonix and Elemental Recycling have done what others could not: they have found technologies that recycle all types of plastic.

The monumental task of recycling the 380 million tons of plastic disposed of each year, that clog the ocean and beaches throughout the world, has eluded us. Around 80 percent of all plastic ends up in the oceans and landfills.

Continue reading “All types of plastics now recyclable thanks to two companies” »

Logic gates are the fundamental components of computer processors. Conventional logic gates are electronic—they work by shuffling around electrons—but scientists have been developing light-based optical logic gates to meet the data processing and transfer demands of next-generation computing.

New optical chirality logic gates developed by researchers at Aalto University operate about a million times faster than existing technologies, offering ultrafast processing speeds.

The new approach uses circularly polarized light as the input signal. The logic gates are made from crystalline materials that are sensitive to the handedness of a circularly polarized light beam—that is, the light emitted by the crystal depends on the handedness of the input beams. This serves as the basic building block for one type of logic gate (XNOR), and the remaining types of logic gates are built by adding filters or other optical components.

Non-metal nitrides are compounds in which nitrogen and non-metallic elements are linked by covalent bonds. Because of their technologically interesting properties, they have increasingly become the focus of materials research. In Chemistry—A European Journal, an international team with researchers from the University of Bayreuth presents previously unknown phosphorus-nitrogen compounds synthesized under very high pressures.

They contain structural units whose existence could not be empirically proven before. The study exemplifies the great, as yet untapped potential of high-pressure research for nitrogen chemistry.

The researchers succeeded in synthesizing a previously unknown modification of the phosphorus nitride P₃N₅, the polymorph δ-P₃N₅, at a pressure of 72 gigapascals. At 134 gigapascals, the phosphorus nitride PN₂ formed in the diamond anvil cell. Both compounds are classified as ultra-incompressible materials with the bulk moduli above 320 GPa.

The new sodium-sulfur batteries are also environmentally friendly, driving the clean energy mission forward at a low cost.

To realize the universal goal of net-zero emissions by 2050, the world is keenly looking at advancements in battery technology. Lower costs, higher capacity, and optimal utilization of scarce natural resources are expected to play a major role in taking the mission forward.

Their findings were published in Advanced Materials.

Continue reading “A novel sodium-sulphur battery has 4 times the capacity of lithium-ion batteries” »

A simple alloy has claimed the crown for toughest material ever recorded. In a new study, a team led by researchers at Berkeley Lab ran the alloy through a series of tests and discovered not only its incredible toughness, but high strength and ductility that actually improve in colder temperatures, unlike most known materials.

The alloy in question contains chromium, cobalt and nickel (CrCoNi), and it belongs to a class of metals called high entropy alloys (HEAs). Most alloys are made up of one dominant element with smaller amounts of others added in, but HEAs contain equal amounts of each element. This can give them some impressive properties, such as high strength-to-weight ratios, an elastic modulus that rises with the temperature, or ultra strength and ductility.

In previous work, the researchers found that CrCoNi showed high strength and toughness at low temperatures of around −196 °C (−321 °F). For the new study, the team investigated how it would hold up at even colder temperatures of −253 °C (−424 °F), at which helium exists as a liquid. And sure enough, its toughness hit new heights in preventing cracks propagating.

A textbook theory for the freezing of water also explains the growth of a new phase in a more complicated phase transition of a different material.

When water freezes, the ice forms first in “nuclei”—tiny seed crystals that can grow or shrink and survive only if they reach a minimum size—at least according to the textbook theory. Researchers have now shown that this understanding also applies to a more complicated phase transition in vanadium dioxide (VO₂), a material whose electrical properties and crystal structure both change at its so-called metal-to-insulator phase transition [1]. The team measured the threshold size for the “seeds” that drive this transition and demonstrated a new technique for studying crystal structure transitions. The result suggests that the classical nucleation theory is valid for a range of materials that are important in areas such as catalysis, lasers, and alloy and ceramic manufacturing.

Place a bucket of purified water in a subfreezing-temperature environment, and tiny ice seeds will start forming. Many will quickly dissolve, but those that are larger than a certain threshold size will grow and eventually merge to make a single block of ice. This view of crystallization, associated with classical nucleation theory, has been well accepted for the water–ice transition. Junqiao Wu of the University of California, Berkeley, and his colleagues wanted to test whether the same nucleation phenomenon is at play in VO₂ when it makes a transition from one crystalline structure to another.

The asteroid strike simulation website lets users customize material, size, and speed then witness the destruction, in the name of science.