Category Chemistry/Nanotechnology

Plants like the Jewelweed (Impatiens capensis; or commonly, spotted touch-me-not) use stress ingeniously for the ballistic dispersal of their seeds. The plant stores energy in its seed pods in the form of inbuilt stresses by controlling tissue hydration. When gently touched, these pods explode and curl up to launch their seeds. Using a similar concept, S. Sundaram and coworkers demonstrate the use of 3D-printing to fabricate flat electronic composites with residual stress in specific regions. Credit: Massachusetts Institute of Technology

Researchers from MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) and colleagues report a printable structure that begins to fold itself up as soon as it’s peeled off the printing platform...

1. (Schematic diagram of mushroom-shaped structure fabrication)
2. SEM image of mushroom-shaped structure
3. Image of superomniphobic property of different types of liquid

Scientists have developed a fabrication technology that can inexpensively produce surfaces capable of repelling liquids, including water and oil. The team used the photofluidization of azobenzene molecule-containing polymers to generate a superomniphobic surface which can be applied for developing stain-free fabrics, non-biofouling medical tubing, and corrosion-free surfaces. Mushroom-shaped surface textures, also called doubly re-entrant structures, are known to be the most effective surface structure that enhances resistance against liquid invasion, thereby exhibiting superior superomniphobic property.

However, the exist...

Electrotunable nanoplasmonic liquid mirror. Nature Materials, 2017; DOI: 10.1038/nmat4969

By finely tuning the distance between nanoparticles in a single layer, researchers have made a filter that can change between a mirror and a window. The development could help scientists create special materials whose optical properties can be changed in real time. These materials could then be used for applications from tuneable optical filters to miniature chemical sensors. Creating a ‘tuneable’ material has been a challenge because of the tiny scales involved. In order to tune the optical properties of a single layer of nanoparticles – which are only tens of nanometres in size each – the space between them needs to be set precisely and uniformly.

To form the layer, the team from Imperial College Lo...

Representative HAADF images and particle size distributions for the unsupported AuPd-PVP sol in the fresh (A to C) and after a CH4 oxidation reaction (D to F). CREDIT Graham J. Hutchings and Christopher J. Kiely

Liquid methanol is widely used as a feedstock for other chemicals and also has considerable potential as an alternative fuel source. However, converting methane—the primary component of abundant natural gas—into methanol is currently achieved by an indirect process which requires high heat and pressure. Now researchers have discovered a new approach that allows the direct conversion of methane to methanol utilizing molecular oxygen under much milder reaction conditions.

A team has used colloidal gold-palladium (Au-Pd) nanoparticles to directly oxidize methane to methanol with h...