Infrastructure and everyday materials

Researchers from Carnegie Mellon University have found a way to control the size and structure of active colloids while yielding more than 100 times the amount created by earlier fabrication methods. The team's active colloids are linked together using DNA nanostructures – an innovation that makes them flexible, agile, and responsive to signals in their environment. Typically, DNA nanotechnology can only be studied using expensive equipment.

Researchers from Northwestern University, Duke University, and Cornell University have developed the first two-dimensional mechanically interlocked material. Looking like the interlocking links in chainmail, the nanoscale material exhibits exceptional flexibility and strength. With further work, this material holds promise for use in high-performance, light-weight body armor and other uses that demand lightweight, flexible, and tough materials. "We made a completely new polymer structure," said William Dichtel, the study's corresponding author.

Researchers from the University of California, Davis, have developed a new technique to trap clusters of platinum atoms in nanoscale islands. Previous work had shown that platinum arranged in clusters of a few atoms on a surface makes a better hydrogenation catalyst than either single platinum atoms or larger nanoparticles of platinum. But such small clusters tend to clump easily into larger particles, losing efficiency.

Materials that conduct electricity well, like metals, also tend to conduct heat. But researchers at Drexel University, Villanova University, Temple University, Bryn Mawr College, Rice University, and Université catholique de Louvain in Belgium have discovered that MXenes, a type of material known for its excellent electrical conductivity, actually have very low thermal conductivity. This discovery challenges the usual link between electrical and heat conduction and could lead to new developments in building materials, performance apparel, and energy storage solutions.

Scientists at Rice University have made it possible to capture clear images of objects through hot windows. The core of this breakthrough lies in the design of nanoscale resonators, which work like miniature tuning forks trapping and enhancing electromagnetic waves within specific frequencies. The resonators are made from silicon and organized in a precise array that allows fine control over how the window emits and transmits thermal radiation. One immediate application is in chemical processing, in which chemical reactions inside high-temperature chambers need to be monitored.

Researchers from the University of Central Florida have developed a new technique to detect long-wave infrared photons of different wavelengths based on a nanopatterned graphene. "No present cooled or uncooled detectors offer such dynamic spectral tunability and ultrafast response," said Debashis Chanda, the scientist who led this study.

Researchers from the University of Chicago; the University of California, Berkeley; Northwestern University; the University of Colorado Boulder; and  the U.S. Department of Energy’s Argonne National Laboratory have developed a new technique for growing quantum dots – nanocrystals used in lasers, quantum light-emitting diode (QLED) televisions, and solar cells. The researchers replaced organic solvents typically used to create quantum dots with molten salt – literally superheated sodium chloride of the type sprinkled on baked potatoes.

Researchers from Northwestern University and the University of California, Los Angeles, have developed a new strategy that prevents frost formation before it begins. The researchers discovered that tweaking the texture of any surface and adding a thin layer of graphene oxide prevents frost from forming on the surface for one week, or potentially even longer. This is 1,000 times longer than current, state-of-the-art anti-frosting surfaces. As an added bonus, the new scalable surface design also is resistant to cracks, scratches, and contamination.

Researchers at William & Mary have measured the strength and stretchability of minuscule nanofibrils present in the silk spun by the southern house spider. The core of a spider silk strand is composed of two distinct warps that form helical loops around a central foundation fiber. The tiniest fibers, nanofibrils, are spun into a mesh that surrounds those supporting structures. The researchers found that the nanofibrils in the southern house spider’s silk could stretch 11 times their original length, more than twice the amount of any spider silk previously tested.

Researchers from Drexel University, the University of Pennsylvania, and Accenture Labs (San Francisco, CA), and Corporal Michael J. Crescenz Veterans Affairs Medical Center (Philadelphia, PA) have built a textile energy grid that can be wirelessly charged. The grid was printed on nonwoven cotton textiles with an ink composed of MXene, a type of nanomaterial that is both conductive and durable enough to withstand the folding, stretching, and washing that clothing endures.