News from the NNI Community - Research Advances Funded by Agencies Participating in the NNI

For more than 15 years, researchers at The University of Texas at Dallas and their collaborators in the United States, Australia, South Korea, and China have made artificial muscles by twisting and coiling carbon nanotube or polymer yarns. When thermally powered, these muscles actuate by contracting their length when heated and returning to their initial length when cooled. Such thermally driven artificial muscles, however, have limitations. The researchers have now created powerful, unipolar electrochemical yarn muscles that contract more when driven faster, thereby solving important problems that have limited the applications for these muscles.

For more than 15 years, researchers at The University of Texas at Dallas and their collaborators in the United States, Australia, South Korea, and China have made artificial muscles by twisting and coiling carbon nanotube or polymer yarns. When thermally powered, these muscles actuate by contracting their length when heated and returning to their initial length when cooled. Such thermally driven artificial muscles, however, have limitations. The researchers have now created powerful, unipolar electrochemical yarn muscles that contract more when driven faster, thereby solving important problems that have limited the applications for these muscles.

Researchers at Harvard University have developed a two-millimeter achromatic metalens that can focus red, blue, and green colors without aberrations. Like previous metalenses, this lens uses arrays of titanium dioxide nanofins to focus wavelengths of light and eliminate chromatic aberration. In a virtual or augmented reality platform, the metalens would sit directly in front of the eye, and the display would sit within the focal plane of the metalens.

Researchers at Harvard University have developed a two-millimeter achromatic metalens that can focus red, blue, and green colors without aberrations. Like previous metalenses, this lens uses arrays of titanium dioxide nanofins to focus wavelengths of light and eliminate chromatic aberration. In a virtual or augmented reality platform, the metalens would sit directly in front of the eye, and the display would sit within the focal plane of the metalens.

Bulk hexagonal boron nitride is cheap and easy to obtain, but exfoliating it into atomically thin nanosheets has been a challenge. Now, chemists at Rice University have found a way to get the maximum amount of quality 2D hexagonal boron nitride nanosheets (from its natural bulk form) by processing it with surfactant and water. The surfactant surrounds and stabilizes the nanosheets, preserving their properties.

Bulk hexagonal boron nitride is cheap and easy to obtain, but exfoliating it into atomically thin nanosheets has been a challenge. Now, chemists at Rice University have found a way to get the maximum amount of quality 2D hexagonal boron nitride nanosheets (from its natural bulk form) by processing it with surfactant and water. The surfactant surrounds and stabilizes the nanosheets, preserving their properties.

Kombucha tea, a trendy fermented beverage, has inspired engineers at the U.S. Army's Institute for Soldier Nanotechnologies at MIT and Imperial College London to develop a new way to generate tough, functional materials with a mixture of bacteria and yeast similar to the kombucha mother used to ferment tea. These functional materials, which consist of a dense network of ribbon-like cellulose fibrils, each about 50 nanometers wide and up to 9 micrometers in length, can perform a variety of functions, such as sensing environmental pollutants, purifying water for soldiers in the field, and making smart packaging materials that can detect damage.

Kombucha tea, a trendy fermented beverage, has inspired engineers at the U.S. Army's Institute for Soldier Nanotechnologies at MIT and Imperial College London to develop a new way to generate tough, functional materials with a mixture of bacteria and yeast similar to the kombucha mother used to ferment tea. These functional materials, which consist of a dense network of ribbon-like cellulose fibrils, each about 50 nanometers wide and up to 9 micrometers in length, can perform a variety of functions, such as sensing environmental pollutants, purifying water for soldiers in the field, and making smart packaging materials that can detect damage.

Two studies from researchers at Yale University answer some key questions about two-dimensional (2-D) materials. In one study, the researchers experimentally measured the precise doping effects of small molecules on 2-D materials—a first step toward tailoring molecules for modulating the electrical properties of 2-D materials. In the second study, the researchers looked at the effects of mechanical strain on the ordering of lithium in lithium-ion batteries and demonstrated how much the lithium atoms slow down.

Two studies from researchers at Yale University answer some key questions about two-dimensional (2-D) materials. In one study, the researchers experimentally measured the precise doping effects of small molecules on 2-D materials—a first step toward tailoring molecules for modulating the electrical properties of 2-D materials. In the second study, the researchers looked at the effects of mechanical strain on the ordering of lithium in lithium-ion batteries and demonstrated how much the lithium atoms slow down.