Infrastructure and everyday materials

Flame aerosol synthesis is used to create nanoparticles that serve as key ingredients in inks and air filters. While effective, this technique has limitations, including challenges with manipulating the flame, achieving precise control over the size and distribution of nanoparticles, and cost. Two new studies, from researchers at the University at Buffalo; the U.S.

Researchers from the U.S. Department of Energy’s Lawrence Livermore National Laboratory, Stanford University, and the University of Pennsylvania have developed a technique that enhances the optical absorptivity of metal powders used in 3D printing. The approach, which involves creating nanoscale surface features on metal powders, promises to improve the efficiency and quality of printed metal parts.

Cellulose nanocrystals derived from renewable resources have shown great potential for use in composites, biomedical materials, and packaging. But a major challenge in the production of cellulose nanocrystals is the energy-intensive drying process. To address this issue, a team of researchers from the University of Illinois Urbana-Champaign, Purdue University, and North Carolina Agricultural and Technical State University has introduced a novel multi-frequency ultrasonic drying technology.

Researchers at the City University of New York have experimentally demonstrated that metasurfaces (two-dimensional materials structured at the nanoscale) can precisely control the optical properties of thermal radiation generated within the metasurface itself. This work paves the way for creating custom light sources with unprecedented capabilities. Metasurfaces offer a solution for greater utility by controlling electromagnetic waves through meticulously engineered shapes of nanopillars that are arrayed across their surfaces. 

Researchers from the University of Michigan and Indiana University have shown that by combining an electron microscope, a small sample holder with microscopic channels, and computer simulations, it is possible to see how nanoscale building blocks can rearrange into different organized structures. In the study, the researchers suspended nanoparticles in tiny channels of liquid on a microfluidic flow cell.

Researchers from North Carolina State University, the Leibniz Institute of Polymer Research Dresden in Germany, Technische Universität Dresden in Germany, and Otto von Guericke University Magdeburg in Germany have embedded gold nanorods in hydrogels that can be processed through 3D printing to create structures that contract when exposed to light and expand when the light is removed. When the hydrogel structures are exposed to light, the embedded gold nanorods convert that light into heat.

Scientists from the U.S. Department of Energy’s Pacific Northwest National Laboratory have discovered that reducing graphene oxide membranes with ultraviolet light alters the oxygen functional groups on the graphene oxide surface. This modification results in a novel separation mechanism that is selective for charge rather than size. Exposure to ultraviolet light selectively removed hydroxyl groups from the graphene oxide planes, leading to enhanced interactions of metal cations with functional groups located at the edges of the graphene oxide.

Scientists from the U.S. Department of Energy's (DOE) Argonne National Laboratory (ANL) and the University of Chicago have developed a new technique to determine how nanoparticles move and interact with one another in soft matter when subjected to an applied force or temperature change. At the start, three bands of nanoparticles formed: fast moving, slow moving, and static. After 15 seconds, the fast-moving band vanished. About 40 seconds later, the three bands returned.

University of California, Irvine scientists have discovered a one-dimensional nanoscale material whose color changes as temperature changes. "We found that we can make really small and sensitive thermometers," said Maxx Arguilla, one of the scientists involved in this study. Arguilla likened the thermometers to "nano-scale mood rings," referring to the jewelry that changes color depending on the wearer's body temperature.

Researchers from Cornell University have used solubility rather than entropy to overcome thermodynamic constraints and create high-entropy oxide nanocrystals at lower temperatures. High-entropy materials are formed by mixing five or more elements within the structure of a crystal.