nanosize

joshbyard:

Hacking Spider Silk to Create Nano-Electronic Components:

As a protein-based polymer, spider silk is naturally insulating, so the researchers are exploring what happens when it’s coated with iodine, gold, or carbon nanotubes. In all three cases, the silk turned into a more conductive fiber. However, “gold really likes spider silk,” Steven told scientists at the American Physical Society’s March meeting in Boston. “Gold nanoparticles adhere to spider silk very well.”

The team started with 3.5-μm-wide silk harvested from Nephila clavipes, the golden orb-weaving spider. They placed the silk in a vacuum chamber and coated it with gold. The resulting fiber had electrical conductivity from the gold plus flexibility from the silk, and it measured only 1/25th the diameter of a human hair. That allowed the fibers to be used—even without conductive paste—as contacts on tiny organic crystals, which the lab chills to cryogenic temperatures to study their superconductivity.

Standard wires made of gold or other metals aren’t elastic enough and tend to lose contact with the soft organic crystals as temperatures change. The group found that the gold-coated silk fibers worked as contacts down to the lowest temperature they tested at, about 260 millikelvin.

The researchers also coated the silk with carbon nanotubes, creating highly sensitive strain sensors. Those could be used as heart-pulse monitors, Steven suggests.

Meanwhile, the iodine-doped silk showed changes in conductivity that depended on relative humidity. But the science didn’t stop there.

Steven heated the iodine-doped silk in an argon atmosphere to 800°C, creating a pyrolyzed, carbon-coated fiber that turned out to be a p-type semiconductor. The researchers then used those fibers to make filaments for incandescent bulbs.

Steven says the group is working on using the functionalized silk to make electronic components, such as diodes, inductors, and capacitors. It should be possible to build a field-effect transistor out of the semiconducting version of the material. (Other labs have already used silk from the silk moth, Bombyx mori, as the gate insulator in a transistor.)

Conducting and semiconducting fibers could be readily woven into fabrics to make so-called smart textiles, such as shirts that could sense temperature or other environmental changes. Combining the Florida State research with efforts under way elsewhere to create spider silk artificially might allow engineers to mass-produce fibers with tunable electrical properties, Steven says.

(via Spider Silk Weaves New Path for Electronics - IEEE Spectrum)

(Photo: Spider Silk Glands Source)

A carbon nanotube sponge developed with help from ORNL researchers holds potential as an aid for oil spill cleanup.

Simulations at ORNL explained how the addition of boron atoms encouraged the formation of so-called “elbow” junctions that help the nanotubes grow into a 3-D network.

Researchers have created a new nanocomposite made of graphene and protein fibrils: a special paper, which combines the best features of both components. 

“Graphene paper” has shape memory features

Graphene is mechanically strong and electrically conductive, as well as, highly water repellent by nature. On the other hand, the protein fibrils are biologically active and can bind water. This allows the new material to absorb water and to change shape under varying humidity conditions. Furthermore, the “graphene paper” has shape memory features such that it can deform when adsorbing water, and recover the original shape upon drying. This could be used, for example, either in water sensors or humidity actuators.

(Source: ethlife.ethz.ch)

joshbyard:

National Nanotechnology Initiative Officially On Track

Just four months after the National Nanotechnology Initiative (NNI) responded to the President’s Council of Advisors on Science and Technology’s (PCAST) 2010 report on the status of nanotechnology, PCAST has offered up a new assessment.

While the PCAST report on the NNI in 2010 wanted to see greater efforts towards commercialization and some attempt to address environmental, health and safety (EHS) concerns, this time they just wanted to see how well the NNI had done in meeting their previous recommendations.

(via President’s Council Wants a Few More Things from the National Nanotechnology Initiative - IEEE Spectrum)

The nanobama structures are made of carbon nanotubes, and the pictures were taken using optical and electron microscopes. Carbon nanotubes (CNTs) are tiny hollow cylinders of carbon; the diameter of a CNT is tens of thousands of times smaller than a human hair, and CNTs are several times stronger and stiffer than steel. CNTs are grown by a high-temperature chemical reaction, using patterns of nanoscale metal catalyst particles arranged in the shapes of the faces, text, and flags that you see in the images. Each face contains millions of parallel nanotubes, standing vertically on the substrate like a forest of trees. If you were standing next to the nanotubes as they grow, and each nanotube was a 1 foot (0.3 meter) diameter tree, the trees would be growing at over 500 miles per hour! The nanobama faces are approximately 0.5 millimeter wide, or about ten times the width of a human hair.