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Superstrong Nanofibers | Earth Wise

March 5, 2021 By EarthWise Leave a Comment

MIT research team has developed superstrong nanofibers

Self-assembly is a ubiquitous process in the natural world that leads to the formation of the DNA double helix, the creation of cell membranes, and to many other structures.   Scientists and engineers have been working to design new molecules that assemble themselves in water for the purpose of making nanostructures for biomedical applications such as drug delivery or tissue engineering.  For the most part, the materials created in this way have been chemically unstable and tended to degrade rapidly, especially when the water is removed.

A team at MIT recently published a paper describing a new class of small molecules they have designed that spontaneously assemble into nanoribbons with unprecedented strength and that retain their structure outside of water.

The material is modeled after a cell membrane.  Its outer part is hydrophilic (it likes to be in water) and its inner part is hydrophobic (it tries to avoid water.)  This configuration drives the self-assembly to create a specific nanostructure and by choosing the appropriate chemicals to form the structures, the result was nanoribbons in the form of long threads that could be dried and handled.  The resultant material in many ways resembles Kevlar.   In particular, the threads could hold 200 times their own weight and have extraordinarily high surface areas.  The fibers are stronger than steel and the high surface-to-mass ratio offers promise for miniaturizing technologies for such applications as pulling heavy-metal contaminants out of water and for use in electronic devices and batteries.

The goal of the research is to tune the internal state of matter to create exceptionally strong molecular nanostructures.  The potential for important new applications is considerable and exciting.

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Researchers construct molecular nanofibers that are stronger than steel

Photo, posted June 19, 2007, courtesy of Andrew Hitchcock via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Artificial Aquatic Polyps | Earth Wise

September 16, 2020 By EarthWise Leave a Comment

Aquatic robots can clean water

Corals are often mistaken for rocks because of their hardened surfaces.  And, since they attach or “take root” to the sea floor, they are often mistaken for plants.  But unlike rocks, corals are alive.  And unlike plants, corals do not make their own food.  Corals are actually animals. 

Most of these structures that we call “coral” are made up of hundreds to thousands of tiny coral creatures called polyps.  A coral polyp, which is often no thicker than a nickel, has a saclike body and mouth that is encircled by stinging tentacles.  Polyps are responsible for a host of ecosystem services, including nourishing corals, and aiding coral survival by generating self-made currents through the motion of their soft bodies. 

Inspired by these marine organisms, researchers from the University of Warwick in the UK and Eindhoven University of Technology in the Netherlands have collaborated to develop an artificial aquatic polyp capable of removing contaminants from water.  The 1 square centimeter wireless robot polyp can attract, grasp, and release objects, moving under the influence of a magnetic field and whose “tentacles” are triggered by light. 

The next step for the researchers is to see if the technology can be successfully scaled up from laboratory to pilot scale.  In order for that to happen, the team has to design an array of artificial polyps capable of working harmoniously together.   

Corals are an incredibly important part of ocean ecosystems.  And while it remains to be seen how much value artificial polyps can achieve in future applications, it serves as another example of scientists emulating nature to create more sustainable designs. 

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Aquatic robots can remove contaminant particles from water

An artificial aquatic polyp that wirelessly attracts, grasps, and releases objects

Photo, posted April 14, 2011, courtesy of Derek Keats via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Urban Streams Are Breeding Superbugs

August 14, 2018 By EarthWise Leave a Comment

https://earthwiseradio.org/wp-content/uploads/2018/08/EW-08-14-18-Urban-Streams.mp3

City streams are subjected to a constant onslaught of synthetic chemicals found in pharmaceuticals and personal care products. Wastewater treatment facilities are not designed to filter out these compounds. Instead, they flow into surface waters where they impact aquatic organisms like microbes – which perform key ecosystem services like removing excess nutrients and breaking down leaf litter.

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Dioxane And Drinking Water

October 24, 2017 By EarthWise Leave a Comment

https://earthwiseradio.org/wp-content/uploads/2017/10/EW-10-24-17-Dioxane-And-Drinking-Water.mp3

A byproduct of plastics production, dioxane is a clear, synthetic, liquid solvent that easily mixes with water.  It’s frequently used in paint strippers, dyes, and varnishes, as well as shampoos and body washes – particularly those that are sudsy.  Dioxane doesn’t really biodegrade and is widely regarded as a contaminant.    

[Read more…] about Dioxane And Drinking Water

Removing Heavy Metals From Water

September 7, 2017 By EarthWise

https://earthwiseradio.org/wp-content/uploads/2017/09/EW-09-07-17-Removing-Heavy-Metals.mp3

Clean and abundant water is the most essential need for all human societies and the supply of it is threatened by increasing populations and volatile climate patterns.   The quality of water is threatened by a host of contaminants, most of our own making.

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Septic Systems and Water Contaminants

August 28, 2017 By EarthWise

https://earthwiseradio.org/wp-content/uploads/2017/08/EW-08-28-17-Septic-Systems-and-Water-Contaminants.mp3

A recent study has shown that septic systems in the U.S. routinely discharge pharmaceuticals, consumer product chemicals and other potentially hazardous substances into the environment.   The comprehensive study, published in the journal Environmental Science & Technology, raises health concerns since these chemicals can end up in groundwater and drinking water supplies.

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Accidental Ethanol From Carbon Dioxide

December 27, 2016 By EarthWise

https://earthwiseradio.org/wp-content/uploads/2016/12/EW-12-27-16-Accidental-Ethanol.mp3

Scientists at the Oak Ridge National Laboratory in Tennessee were trying to find a series of chemical reactions that could turn carbon dioxide into a useful fuel.  But the unexpected occurred:  they found that the first step in their process actually got the job done all by itself.   The reaction turns CO2 into ethanol, which is already used to power generators and vehicles.

[Read more…] about Accidental Ethanol From Carbon Dioxide

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