Gizmorama - March 1, 2017

Good Morning,

Science is full of sights and sounds...especially in today's issue. Scientists have come up with both a sound-shaping metamaterial and rainbow-emitting materials. What a sensation!

Learn about this and more interesting stories from the scientific community in today's issue.

Until Next Time,
Erin

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*-- Scientists invent new sound-shaping metamaterial --*
FALMER, England - Researchers from the universities of Sussex and Bristol, in England, have invested a new material capable of bending and focusing sound waves.

The super-material is the latest addition to a group of groundbreaking metamaterials -- a class of materials designed to manipulate our physical reality. Scientists have previously designed invisibility cloaks using metamaterials that capture lightwaves.

Precisely shaped collections of sound waves, or sound fields, are used in a variety of technologies, including medical imaging. The new metamaterial can be used to more efficiently manipulate sound waves and create sound fields for a variety of purposes.

The super-material is made up of tiny bricks marked by a coiled interior structure. Each brick can be designed to bend, shape and focus sound waves in a different way, and the bricks can be arranged in a grid to create different sound fields. The size of the brick and the layered grid can be scaled up and down for different tasks.

A small sound field, for example, could be designed to target a tumor with ultrasound waves. A larger layered grid and larger sound field could be applied in a variety of audio technologies.

"Our metamaterial bricks can be 3D printed and then assembled together to form any sound field you can imagine," lead researcher Gianluca Memoli, an informatics research fellow at Sussex, said in a news release. "We also showed how this can be achieved with only a small number of different bricks. You can think of a box of our metamaterial bricks as a do-it-yourself acoustics kit."

The researchers detailed their invention in the journal Nature Communications.

"Our research opens the door to new acoustic devices combining diffraction, scattering and refraction, and enables the future development of fully digital spatial sound modulators, which can be controlled in real time with minimal resources," said Sriram Subramanian, an informatics researcher and head of Sussex's Interact Lab.



*-- Scientists reveal new rainbow-emitting materials --*
OKINAWA, Japan - Scientists at Osaka University in Japan have developed materials that emit a full range of colors. Until now, mechanochromic luminescent, or MCL, materials were only able to emit two colors.

MCL materials produce different colors by switching between stable and metastable states. To get MCL materials to emit more colors, scientists had to develop a material with more metastable states. To do so, researchers designed a new molecule.

The new molecule combines conformationally-switchable phenothiazine, or PTZ, an electron donor, with dibenzophenazine, DBPHZ, an electron acceptor.

"In this structure, the PTZ moiety could take two distinct conformers, which therefore in principle creates in total four metastable states as a whole molecule," Youhei Takeda, a professor of chemical engineering at Osaka, said in a news release.

Tests showed the molecule responds to heating, fuming and grinding by rotating its color between yellow, red and orange. Temperature and pressure changes caused the molecule's components to alter the way they conform to one another.

The material was successfully incorporated into organic light-emitting diode devices, or OLEDs. Importantly, the material also exhibited thermally activated delayed fluorescence properties, TADF. Researchers hope to begin replacing OLED technologies, which require the use of rare metals, with more efficient TADF light emitting devices.

"Our molecule could become a basis for efficient light-emitting devices and pressure- and temperature-responsive sensors in the future," Takeda said.

The new research was published in the journal Chemical Science.

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