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Manufacturing Bits: Oct. 27

Single-molecule memory switches; bioindustrial manufacturing.

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Single-molecule switches
A group of researchers have demonstrated a single-molecule switch or electret, a technology that could one day enable a new class of non-volatile memory storage devices.

Yale University, Nanjing University, Renmin University, Xiamen University, and the Rensselaer Polytechnic Institute have demonstrated a single-molecule electret with functional memory.

Still in R&D, molecular switches fall into the field of molecular electronics. They use molecular building blocks that would replace today’s silicon technology, enabling new and tiny electronic components.

An electret itself is a dielectric material, which has a quasi-permanent electric charge, according to researchers. An electret generates internal and external electric fields.

The technology isn’t new. Electrets are made of piezoelectric materials. They are found in electrostatic microphones.

Nonetheless, in theory, a single-molecule electret switches between two electric dipole states by an external electric field, according to researchers from Yale and others. But these switches demonstrate poor electric dipole stability in single molecules.

To develop a single-molecular switch in the lab, researchers inserted an atom of gadolinium (Gd) inside a carbon buckyball, a 32-sided molecule or sometimes called a buckminsterfullerene. Then, researchers devised a transistor-like technology called Gd@C82.

“Here we report the observation of a gate-controlled switching between two electronic states in Gd@C82. The encapsulated Gd atom forms a charged center that sets up two single-electron transport channels. A gate voltage of ±11 V (corresponding to a coercive field of ~50 mV Å–1) switches the system between the two transport channels with a ferroelectricity-like hysteresis loop,” said Kangkang Zhang, a researcher in Nature Nanotechnology, a journal.

“What’s happening is that this molecule is acting as if it has two stable polarization states. We showed that we could make a memory of it – read, write, read, write,” said Mark Reed, the Harold Hodgkinson Professor of Electrical Engineering & Applied Physics at Yale. “The important thing in this is that it shows you can create in a molecule in two states that cause the spontaneous polarization and two switchable states. And this can give people ideas that maybe you can shrink memory down literally to the single molecular level. Now that we understand that we can do that, we can move on to do more interesting things with it.”

Bioindustrial Manufacturing
The U.S. Department of Defense (DoD) has established a new institute to advance the development of non-medical bioindustrial manufacturing technology in the United States.

As part of the plan, the DoD has awarded $87.5 million to create the Bioindustrial Manufacturing And Design Ecosystem (BioMADE) at the University of Minnesota. BioMADE is a nonprofit organization, which was created with the Engineering Biology Research Consortium (EBRC).

BioMADE is the 16th federally-sponsored Manufacturing Innovation Institute (MII) within the Manufacturing USA network. The seven-year award includes at least $87.5 million in federal funds and is being matched by more than $180 million in cost sharing from non-federal sources.

Bioindustrial manufacturing involves the creation of chemical compounds and materials, which enables new products and technologies.

For example, the University of Minnesota is developing products such as anti-biocorrosion coatings for ships and harbors. They are also developing enzymes that can purify drinking water.

Bioindustrial companies are developing fire-resistant composite materials for aerospace applications, next-generation biofuels, and films for electronic touch screens and circuit boards.

Anticipated bioindustrial applications include the following products: chemicals, solvents, detergents, reagents, plastics, electronic films, fabrics, polymers, agricultural products, crop protection solutions, food additives, fragrances, and flavors.

The institute will advance industry-wide standards, tools, and measurements; foundational technologies; foster a bioindustrial manufacturing ecosystem; advance education and workforce development; and support the establishment and growth of supply chain intermediaries that are essential for a robust U.S. bioeconomy.

“The U.S. bio-based economy is thriving at $1 trillion annually and some projections have it growing to as much as $4 trillion in worldwide impact annually over the next 10-20 years. This institute will ensure that this growing national industry is a key part of our Bold North economy. It will accelerate growth of our bioindustrial ecosystem, create jobs for a newly trained workforce, and add to and complement our current industries,” said Christopher Cramer, vice president for research at the University of Minnesota.



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