Researchers at Rice University in Houston, Texas, have developed a new method for performing chemical reactions using water instead of toxic solvents.They call it green chemistry. We wrote about the potential of water over toxic solvents way back in 2008. The idea is now coming to fruition. Baby steps in science.

The scientists created microscopic reactors capable of driving light-powered chemical processes by designing metal complex surfactants (MeCSs) that self-assemble into nanoscale spheres called micelles. This innovation could drastically reduce pollution in industries including pharmaceuticals and materials science, where harmful organic solvents are often necessary.

The new micellar technology represents a step forward in sustainable chemistry. These self-assembled micelles form in water, where their hydrophobic cores provide a unique environment for reactions, even with materials that are typically insoluble in water.

The research team led by Angel Martí, professor and chair of chemistry at Rice, demonstrated that this system can efficiently perform photocatalytic reactions while eliminating the need for hazardous substances. The study was published in Chemical Science Feb. 10.

“Our findings show how powerful molecular design can be in tackling chemical sustainability challenges while maintaining high chemical performance,” Martí said. “We’ve created a tool that could transform how chemical reactions are performed, reducing environmental harm while increasing efficiency.”

How the discovery works

Surfactants are molecules with a dual nature: One part is attracted to water, while the other repels it. When added to water, they naturally form micelles or tiny spheres where the water-avoiding parts gather in the center, creating a small reaction space. The scientists modified these surfactants by adding a light-sensitive metal complex to their structure, making the MeCSs.

The researchers tested different versions of the MeCSs by altering the length of their hydrophobic, or water-repelling, tails. They found that these molecules could form micelles as small as 5-6 nanometers, much smaller than those in similar systems. The team used these micelles to perform a photocatalytic reaction, achieving high yields without needing harmful solvents.

“These micelles act like tiny reaction vessels,” said Ying Chen, first author of this study and a doctoral student in chemistry at Rice. “They enable chemical transformations that wouldn’t normally work in water while being more sustainable than traditional methods.”

Why this matters

Many chemical processes in manufacturing and research rely on organic solvents, which are harmful to the environment and expensive to handle safely. The development of photoactive water-based micelles capable of driving chemical reactions offers a safer, greener alternative. Additionally, the system can be reused, improving its cost-effectiveness and environmental footprint.

In 2008 we reported on the groundbreaking work, thanks to a groundbreaking discovery at Tel Aviv University. Prof. Arkadi Vigalok from the School of Chemistry has discovered a way to use water to make certain steps of a complicated chain of chemical reactions more environmentally-friendly.

Prof. Vigalok’s solution replaces chemical solvents, which can pollute the environment, with water. Though chemists have long thought it possible, Prof. Vigalok’s approach has only rarely been even attempted. His discovery was reported in the journal Angewandte Chemie, International Edition. Once ideas are published in the scientific community they become open-source questions and challenges for the science community around the world to solve.

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Imagine a sweater that powers electronics to monitor your health or charge your mobile phone while running. This development faces challenges because of the lack of materials that both conduct electricity stably and are well suited for textiles. Now a research group, led by Chalmers University of Technology in Sweden, presents an ordinary silk thread, coated with a conductive plastic material, that shows promising properties for turning textiles into electricity generators. Imagine a dress you are wearing that lights up the night – literally!

Thermoelectric textiles convert temperature differences, for example between our bodies and the surrounding air, into an electrical potential. This technology can be of great benefit in our everyday lives and in society. Connected to a sensor, the textiles can power these devices without the need for batteries. These sensors can be used to monitor our movements or measure our heartbeat.

Since the textiles must be worn close to the body, the materials used in them must meet high demands on safety and flexibility. The silk thread that the researchers tested has a coating made of a conducting polymer. It is a plastic material with a chemical structure that makes the material electrically conductive and well adapted to textiles.

“The polymers that we use are bendable, lightweight and are easy to use in both liquid and solid form. They are also non-toxic,” says Mariavittoria Craighero, who is a doctoral student at the Department of Chemistry and Chemical Engineering at Chalmers University of Technology, and first author of a recently published study.

Enhanced stability and conductivity

The method used to make the electrically conductive thread is the same as used in previous studies within the same research project.  Previously, the thread contained metals to maintain its stability in contact with air. Since then, advances have been made to manufacture the thread with only organic (carbon-based) polymers. In the current study, the researchers have developed a new type of thread with enhanced electrical conductivity and stability.

Related: Thermoelectric ink changes on this stamp

“We found the missing piece of the puzzle to make an optimal thread – a type of polymer that had recently been discovered. It has outstanding performance stability in contact with air, while at the same time having a very good ability to conduct electricity. By using polymers, we don’t need any rare earth metals, which are common in electronics,” says Mariavittoria Craighero.

To show how the new thread can be used in practice, the researchers manufactured two thermoelectric generators – a button sewn with the thread, and a piece of textile with sewn-in threads. When they placed the thermoelectric textiles between a hot and a cold surface, they could observe how the voltage increased on the measuring instrument.

The effect depended on the temperature difference and the amount of conductive material in the textile.  As an example, the larger piece of fabric showed about 6 millivolts at a temperature difference of 30 degrees Celsius. In combination with a voltage converter, it could theoretically be used to charge portable electronics via a USB connector.  The researchers have also been able to show that the thread’s performance is maintained for at least a year. It is also machine washable.

“After seven washes, the thread retained two-thirds of its conducting properties. This is a very good result, although it needs to be improved significantly before it becomes commercially interesting,” says Mariavittoria Craighero.

Can meet functions that these textiles require

The thermoelectric fabric and button cannot be produced efficiently outside the lab environment today. The material must be made and sewn in by hand, which is time-consuming. Just sewing it into the demonstrated fabric required four days of needlework. But the researchers see that the new thread has great potential and that it would be possible to develop an automated process and scale up.

“We have now shown that it is possible to produce conductive organic materials that can meet the functions and properties that these textiles require. This is an important step forward. There are fantastic opportunities in thermoelectric textiles and this research can be of great benefit to society,” says Christian Müller, Professor at the Department of Chemistry and Chemical Engineering at Chalmers University of Technology and research leader of the study.

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The earth tones of 15,000 year-old cave paintings were created with natural pigments of yellow and red ochre clay, soot, berries, animal parts and blood.  Most of the world’s languages did not have a word for the color blue 5000 years ago when, sometime before Egypt’s fourth dynasty a clever alchemist heated copper, sand and natron. The resulting powder is composed of tiny crystals of calcium copper silicate (CaCuSi₄O₁₀.)

The Egyptian word for this substance was hsbd-iryt which means artificial lapiz lazuli. Before the discovery of Egyptian blue it was necessary to crush the valuable gemstone Lapiz Lazuli in order to reproduce the colors of rebirth, irtiu and khshdj.

Blue was the color of the heavens, the Phoenix, the primordial flood and the Nile. Egyptian blue spread quickly throughout the Greco-Roman world. The secret of its manufacture was lost during the fourth century A.D. and rediscovered more than 1400 years later by Sir Humphrey Davy of England.

Its use declined when other pigments such as poisonous Prussian blue and carcinogenic cobalt blue became widely available, but its optical and nanotechnology properties has caused a renewed interest in this amazing and beautiful substance.

Egyptian blue emits a strong infrared light when exposed to visible light. Archaeologists use this fluorescence to reveal the presence of Egyptian blue in ancient art and also to reveal hidden detail.  Tina Salguero, a chemist and materials scientist at the University of Georgia, in Athens, Ga was quoted by Inside Science News as saying, “Egyptian blue is composed of abundant and inexpensive elements — calcium, copper, silicon, and oxygen — in contrast to other near-infrared-emitting materials that contain rare earth elements.

This feature could provide economic and environmental benefits to future applications.” It is only speculation but one such application might involve energy efficient light emitting diode light sources. For example, most green solid state lasers begin with a strong infrared light source which passes through a frequency doubling crystal in order to change it to green light wavelengths.

Other possibilities include medical applications. Egyptian blue’s near infrared wavelength passes through human tissue more easily than visible light.

Egyptian blue’s discovery, loss and rediscovery are important reminders that sometimes we must study our past in order to discover our path to the future.

Images of blue Egyptian wallpaper and Egyptian wall painting from Shutterstock

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In 1914, thirty-five years before Chaim Weizmann (pictured center beside Einstein) would become Israel’s first president, he discovered a fermentation process for harnessing bacteria to produce large quantities of useful chemicals. For this discovery, Weizmann was called the father of industrial fermentation. The bacterium Clostridium acetobutylicum was named the Weizmann organism, giving him a taste of fame long before his Israeli political career. His process of Acetone Butanol Ethanol (ABE) fermentation helped produce explosives for World War I and now a team of chemical engineers at UC Berkley are close to perfecting his process for the efficient production of biofuels.

Weizmann’s ABE process was initially used to produce acetone which was used in the World War I explosive cordite. Like Alfred Nobel and Albert Einstein, Chaim Weizmann might have wondered about the moral implications of inventing something which would be used as a tool of war.

But Weizmann once said,

“I trust and feel sure in my heart that science will bring to this land both peace and a renewal of its youth, creating here the springs of a new spiritual and material life. […] I speak of both science for its own sake and science as a means to an end.”

Related: visit the Clore Science Garden in the Weizmann Institute of Science

Dean Toste, Harvey Blanche and Douglas Clark are well on their way towards fulfilling Weizmann’s dream. Harvey Blanche explained that their variation on Weizmann’s fermentation process could efficiently convert corn, eucalyptus, sugar cane, grass and other fast-growing plants and trees into the ACE mixture. Then a catalyst developed by Dean Toste converts this mixture into a high-energy biofuel. Their results are published in Nature.

“You can take a wide variety of sugar sources – from corn, sugar cane, molasses to woody biomass or plant biomass – and turn it into a diesel product using this fermentation process,” said Harvey Blanch in an SFGate article, adding that about 90 percent of the raw material remains in the finished product, reducing the loss of carbon. “Grasses are also a possible source. Eucalyptus could also be used. Anything that’s fast-growing.”

California is expected to be the first niche market to use this new biofuel, although it would likely take about ten years to go to market.

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Scientists at Technion, Israel’s institute of technology recently found a new way to store solar energy. Their method utilizes a substance that some of us are all too familiar with, iron oxide– otherwise known as rust. This research entitled Resonant light trapping in ultrathin films for water was published in the November 11, 2012 issue of Nature Materials and may help solve the problem of solar energy storage by enabling a more efficient and direct conversion between solar energy and hydrogen.

I grew up in a region that was once known as the rust belt. Iron foundries, heavy industry and heavy cars were plentiful in the upper Midwestern US. Winters were icy so governments used salt to help make the roads safer. Unfortunately this also made automobiles rustier.

Comedian Dave Barry once joked that American cars were made out of compressed rust. Salt-encrusted lumps of grey slush clung to the bottoms of cars and performed the alchemy of converting iron and gleaming steel into crumbling heaps of orange-red rust.

Actually it wasn’t alchemy, it was ordinary chemistry which is a little too complicated to explain here, but parts of the reaction can be simplified to something like this:

2Fe(s) + 2H2O(l) + O2(g) → 2Fe2+(aq) + 4OH-(aq)  {a bit more magic} → Fe2O3 .nH2O

Iron, water and oxygen combine to make a solution which dries to become rust.

All about rust

Rust crumbles in your hand and stains your skin, your clothes and concrete structures.

Grocery stores once sold a chemical which was supposed to remove rust stains but it was also powerful enough to eat through metal, skin and glass. Since then using a rust remover has become much less dangerous while still removing rust.

A form of rust was used in audio cassette tapes, 8-tracks, floppy disks and the hard drive which is storing this article. In 1976 NASA’s Viking lander arrived on Mars and found– rust.

The 1976 Buick I drove to prom had lost the bottom half of its passenger doors to rust. I once connected a voltmeter to some bolts straddling the rusted-out floor of my father’s car and found that the electrochemical process which gradually turned his 1969 AMC Rambler into a heap of rust also generated about 1/2 volt of electricity. I never patented this corrosion-powered “battery car” as a form of planned-obsolescence Detroit would have loved but I’m beginning to wish I’d saved some of that rust. Will it soon become as valuable as platinum was during the cold fusion fiasco? Might the rust belt prosper from this abundant resource just as Saudi Arabia did from oil and the Canadian Yukon did from gold?

Maybe not. Photovoltaic cells are made out of silicon which is found in desert sand but the price of sand hasn’t gone up very much even as the photovoltaic market grows. It turns out that just as it is for photovoltaic silicon, carbon nanotubes, diamonds and coal; the secret is not in the ingredients it is in the preparation. The Technion researchers discovered how to turn something ordinary into something useful by applying materials science.

The paper’s abstract offers a clue:

Semiconductor photoelectrodes for solar hydrogen production by water photoelectrolysis must employ stable, non-toxic, abundant and inexpensive visible-light absorbers. Iron oxide (α-Fe₂O₃) is one of few materials meeting these requirements, but its poor transport properties present challenges for efficient charge-carrier generation, separation, collection and injection. Here we show that these challenges can be addressed by means of resonant light trapping in ultrathin films designed as optical cavities.

Interference between forward- and backward-propagating waves enhances the light absorption in quarter-wave or, in some cases, deeper subwavelength films, amplifying the intensity close to the surface wherein photogenerated minority charge carriers (holes) can reach the surface and oxidize water before recombination takes place.

The researchers are making use of rust’s light absorbing properties which make those stains so visible on a T-shirt. They’re making use of its stability. Water and oxygen can turn a car into rust, but even a large dose of rust remover won’t turn that rust back into a car. They’re also making use of thin-film optical interference. Look at a pair of anti-reflection eyeglasses, the lens of a camera or binoculars, a soap bubble or a thin oil slick floating on a puddle and you’ll see one of the effects these scientists were taking advantage of.

When light comes across a thin semi-transparent film, some of the light is reflected off the bottom of the film, some is reflected off the top. If the film is just the right thickness, light of a certain wavelength can be made to constructively interfere with its reflection, making that color brighter or destructively interfere making that color dimmer.

In this case the scientists have found a way to enhance the light intensity exactly where it is needed to help separate the water’s hydrogen from its oxygen. The hydrogen can then be stored and used to generate energy when the sun isn’t shining. It’s a pretty neat trick for a lump of rust. Kudos to Hen Dotan, Ofer Kfir, Elad Sharlin, Oshri Blank, Moran Gross, Irina Dumchin, Guy Ankonina and Avner Rothschild for their research.

Photo of rusty shipwreck via Shutterstock
Image of thin film light absorption from  Resonant light trapping in ultrathin films for water in the November 11, 2012 issue of Nature Materials

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FRX Polymers manufactures and markets a range of environmental friendly and inherently flame retardant plastics. The company recently raised $26.6 million in series B venture capital financing from a diverse group of investors including Masdar Capital of Abu Dhabi, Israel Cleantech Ventures (ICV), Capricorn venture capital, SAM private equity and BASF Venture Capital of Europe.  This funding will allow FRX polymer to complete its first full scale production facility in Antwerp, Belgium.

Polystyrene has a Limiting Oxygen Index (LOI) of only 21 percent which means it can maintain a flame in normal air with only 21% oxygen.  Potentially toxic fire retardant chemicals must be added to polystyrene in order to make it a safe building material.

PVC and other halogenated polymers provide slightly better flame resistance (40% LOI for non-plasticized PVC) but they release dioxin and other toxic carcinogens into the environment throughout their life-cycle from production, through use and disposal.

[youtube]http://www.youtube.com/watch?v=t7VeiYL2bBg[/youtube]

FRX’s polyphosphonate homopolymers, copolymers, and oligomer polymer plastics are not halogenated, so they do not release dioxin as PVC does.  FRX-100, a non-halogen phosphorous plastic, has a LOI of 65%. This is the highest LOI of any thermoplastic on the market. It does not produce flaming drips or black smoke.

With a diverse group of investors from the Mideast and Europe, FRX seems poised to introduce a building material which will help protect us from fire and protect future generations from toxic carcinogens.

FRX Polymerswas founded in 2007 and the company operates two pilot plants in Chelmsford, MA and a polymer pilot plant in Switzerland.

::FRX Polmers

Image of green men and jellybear from Shutterstock

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