NanotechnologyEngineers are developing a new method of processing nanomaterials that could lead to faster and cheaper manufacturing of flexible, thin film devices, such as touch screens and window coatings.

The “intense pulsed light sintering” method uses high-energy light over an area nearly 7,000 times larger than a laser to fuse nanomaterials in seconds.

The existing method of pulsed light fusion uses temperatures of around 250 degrees Celsius (482 degrees Fahrenheit) to fuse silver nanospheres into structures that conduct electricity. But the new study, published in RSC Advances and led by Rutgers School of Engineering doctoral student Michael Dexter, shows that fusion at 150 degrees Celsius (302 degrees Fahrenheit) works well while retaining the conductivity of the fused silver nanomaterials.

The engineers’ achievement started with silver nanomaterials of different shapes: long, thin rods called nanowires in addition to nanospheres. The sharp reduction in temperature needed for fusion makes it possible to use low-cost, temperature-sensitive plastic substrates like polyethylene terephthalate (PET) and polycarbonate in flexible devices without damaging them.

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A new method to quickly produce fibers from carbon nanotubes is both handmade and high tech.

The method allows researchers to make short lengths of strong, conductive fibers from small samples of bulk nanotubes in about an hour.

In 2013, Rice University chemist Matteo Pasquali found a way to spin full spools of thread-like nanotube fibers for aerospace, automotive, medical, and smart-clothing applications. The fibers look like cotton thread but perform like metal wires and carbon fibers.

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Carbon NanotubesThe introduction of purified carbon nanotubes appears to have a beneficial effect on the early growth of wheatgrass, according to scientists. But in the presence of contaminants, those same nanotubes could do great harm.

The Rice University lab of chemist Andrew Barron grew wheatgrass in a hydroponic garden to test the potential toxicity of nanoparticles on the plant. To their surprise, they found one type of particle dispersed in water helped the plant grow bigger and faster.

They suspect the results spring from nanotubes’ natural hydrophobic (water-avoiding) nature that in one experiment apparently facilitated the plants’ enhanced uptake of water.

The lab mounted the small-scale study with the knowledge that the industrial production of nanotubes will inevitably lead to their wider dispersal in the environment. The study cites rapid growth in the market for nanoparticles in drugs, cosmetics, fabrics, water filters, and military weapons, with thousands of tons produced annually.

Despite their widespread use, Barron says few researchers have looked at the impact of environmental nanoparticles—whether natural or human-made—on plant growth.

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Researchers have captured organic nanoparticles colliding and fusing on video for the first time.

This unprecedented view of “chemistry in motion” will aid nanoscientists developing new drug delivery methods, as well as demonstrate how an emerging imaging technique opens a new window on a very tiny world.

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MicroscopeA team of engineers has found a simple, economical way to make a nano-sized device that can lift many times its own weight.

Their creation weighs 1.6 milligrams (about as much as five poppy seeds) and can lift 265 milligrams (the weight of about 825 poppy seeds) hundreds of times in a row.

Its strength comes from a process of inserting and removing ions between very thin sheets of molybdenum disulfide (MoS2), an inorganic crystalline mineral compound. It’s a new type of actuator—devices that work like muscles and convert electrical energy to mechanical energy.

The discovery—an “inverted-series-connected (ISC) biomorph actuation device”—appears in Nature.

“We found that by applying a small amount of voltage, the device can lift something that’s far heavier than itself,” says Manish Chhowalla, professor and associate chair of the materials science and engineering department of in the School of Engineering at Rutgers University.

“This is an important finding in the field of electrochemical actuators. The simple restacking of atomically thin sheets of metallic MoS2 leads to actuators that can withstand stresses and strains comparable to or greater than other actuator materials.”

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Researchers have found a way to use magnetic nanoparticle clusters to punch through biofilms to reach bacteria that can foul water treatment systems.

The nanoclusters then deliver bacteriophages—viruses that infect and propagate in bacteria—to destroy the bacteria, usually resistant to chemical disinfection.

Without the pull of a magnetic host, these “phages” disperse in solution, largely fail to penetrate biofilms and allow bacteria to grow in solution and even corrode metal, a costly problem for water distribution systems.

The Rice University lab of environmental engineer Pedro Alvarez and colleagues in China developed and tested clusters that immobilize the phages. A weak magnetic field draws them into biofilms to their targets.

“This novel approach, which arises from the convergence of nanotechnology and virology, has a great potential to treat difficult-to-eradicate biofilms in an effective manner that does not generate harmful disinfection byproducts,” Alvarez says.

Biofilms can be beneficial in some wastewater treatment or industrial fermentation reactors owing to their enhanced reaction rates and resistance to exogenous stresses, says graduate student and co-lead author Pingfeng Yu.

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By: Chenfeng Ke, Dartmouth College

Nanomachines are tiny molecules – more than 10,000 lined up side by side would be narrower than the diameter of a human hair – that can move when they receive an external stimulus. They can already deliver medication within a body and serve as computer memories at the microscopic level. But as machines go, they haven’t been able to do much physical work – until now. The Conversation

My lab has used nano-sized building blocks to design a smart material that can perform work at a macroscopic scale, visible to the eye. A 3-D-printed lattice cube made out of polymer can lift 15 times its own weight – the equivalent of a human being lifting a car.

Nobel-winning roots are rotaxanes

The design of our new material is based on Nobel Prize-winning research that turned mechanically interlocked molecules into work-performing machines at nanoscale – things like molecular elevators and nanocars.

Rotaxanes are one of the most widely investigated of these molecules. These dumbbell-shaped molecules are capable of converting input energy – in the forms of light, heat or altered pH – into molecular movements. That’s how these kinds of molecular structures got the nickname “nanomachines.”

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By: Mike Williams, Rice University

Graphene

Rice University researchers have modeled a nanoscale sandwich, the first in what they hope will become a molecular deli for materials scientists.

Their recipe puts two slices of atom-thick graphene around nanoclusters of magnesium oxide that give the super-strong, conductive material expanded optoelectronic properties.

Rice materials scientist Rouzbeh Shahsavari and his colleagues built computer simulations of the compound and found it would offer features suitable for sensitive molecular sensing, catalysis and bio-imaging. Their work could help researchers design a range of customizable hybrids of two- and three-dimensional structures with encapsulated molecules, Shahsavari said.

The research appears this month in the Royal Society of Chemistry journal Nanoscale.

The scientists were inspired by experiments elsewhere in which various molecules were encapsulated using van der Waals forces to draw components together. The Rice-led study was the first to take a theoretical approach to defining the electronic and optical properties of one of those “made” samples, two-dimensional magnesium oxide in bilayer graphene, Shahsavari said.

“We knew if there was an experiment already performed, we would have a great reference point that would make it easier to verify our computations, thus allowing more reliable expansion of our computational results to identify performance trends beyond the reach of experiments,” Shahsavari said.

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By using one of the world’s most powerful electron microscopes, a team of researchers from Lawrence Berkeley National Laboratory has successfully mapped the exact location and chemical type of 23,000 atoms in a nanoparticle made of iron and platinum. The team believes this work could reveal more information about material properties at the single-atom level, opening the doors to improving magnetic performance for next-generation hard drives.

“Our research is a big step in this direction. We can now take a snapshot that shows the positions of all the atoms in a nanoparticle at a specific point in its growth,” says Mary Scott, who conducted the research. “This will help us learn how nanoparticles grow atom by atom, and it sets the stage for a materials-design approach starting from the smallest building blocks.”

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Nano-chimney to Cool Circuits

Overheating has emerged as a primary concern in the development of new electronic devices. A new study from Rice University looks to provide a solution to that, offering a strategy to vent heat away from nano-electronics through cone-like chimneys.

By putting these “chimneys” between the graphene and nanotube, the researchers effectively eliminate a barrier that typically blocks heat from escaping.

This from Rice University:

Researchers at Rice University discovered through computer simulations that removing atoms here and there from the two-dimensional graphene base would force a cone to form between the graphene and the nanotube. The geometric properties of the graphene-to-cone and cone-to-nanotube transitions require the same total number of heptagons, but they are more sparsely spaced and leave a clear path of hexagons available for heat to race up the chimney.

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