Scientists film chemical bond making, breaking

Everything depends on chemical bonds. Without chemical bonds, everything would fall apart. And yet, scientists don't entirely understand how chemical bonding works.

Now, for the first time, scientists have filmed chemical bond making and breaking in action. The breakthrough -- described this week in the journal Science Advances -- promises to offer scientists new insights into this fundamental atomic phenomenon.

The main reason chemical bonding isn't well understood is that the processes happen on such a small scale. But atoms and their bonds aren't just tiny, they're also unruly. Atoms don't like to sit still.

Luckily, a team of researchers from Britain and Germany have developed a way to trap atoms so they can be imaged using technologies like atomic force microscopy and scanning tunnelling microscopy.

Nanocatalysts feature carbon nanotubes, the hollow cylinders of which feature diameters just wide enough to capture single molecules. These nanotubes act like atomic test tubes.

"Nanotubes help us to catch atoms or molecules, and to position them exactly where we want. In this case we trapped a pair of rhenium (Re) atoms bonded together to form Re2," study author Andrei Khlobystov, professor of chemistry at the University of Nottingham, said in a news release. "Because rhenium has a high atomic number it is easier to see in TEM than lighter elements, allowing us to identify each metal atom as a dark dot."

Scientists have previously used electron beams to simultaneously image and incite atomic activity -- to both catalyze and record chemical reactions. The method is known as transmission electron microscopy, and for the latest research, scientists used the technique to watch Re2 bond with carbon nanotubes.

"As we imaged these diatomic molecules by the state of the art chromatic and spherical aberration corrected SALVE TEM, we observed the atomic-scale dynamics of Re2 adsorbed on the graphitic lattice of the nanotube and discovered that the bond length changes in Re2 in a series of discrete steps," said Ute Kaiser, professor at Ulm University in Germany.

The imaging experiments showcased a pair of Re2 atoms walking across the surface of the nanotubes.

"It was surprisingly clear how the two atoms move in pairs, clearly indicating a bond between them. Importantly, as Re2 moves down the nanotube, the bond length changes, indicating that the bond becomes stronger or weaker depending on the environment around the atoms," said Ulm University researcher Kecheng Cao.

The recordings of the movements of the two atoms revealed a series of vibrations as their bond was stretched apart. When the bond ultimately broke, the vibrations ceased. These observations of bond making and breaking could help scientists better understand the magnetic, electronic and catalytic properties of materials.

"To our knowledge, this is the first time when bond evolution, breaking and formation was recorded on film at the atomic scale. Electron microscopy is already becoming an analytical tool for determining structures of molecules," said Khlobystov. "We are now pushing the frontiers of molecule imaging beyond simple structural analysis, and towards understanding dynamics of individual molecules in real time."

Designer hopes green lingerie takes off
Paris (AFP) Jan 19, 2020 - In a tiny workshop in central Paris, Paloma Casile puts finishing touches on eco-friendly lingerie that she hopes will catch on at an international show a few days hence.

Below her chic little shop on the Rue du Jour, the designer pieces together bits of lace, sometimes combined with lurex, taking care to gather up scraps to be used in other models or donated to fashion schools.

"I was always careful when it came to cutting, I have worked in factories and seen the waste" generated by industrial processes, says the 30-year-old who intends to create another line to be made in Morocco.

Casile launched her eponymous line in 2012, with most suppliers in France and a standardised production process to limit losses.

All the fittings are identical, "and they're made from zamak, which requires half the water compared to other metals," she notes in reference to an alloy of zinc, aluminium, magnesium and copper.

Casile also limits her range of colours and uses certified Oeko-tex dyes that are free of toxic substances.

Finally, she repairs her wares for up to four years.

"Ok, it keeps the client on board, but it is also with a view towards not seeing them thrown away," she explains.

The approach has begun to gain ground in the fashion industry as environmental concerns encourage more and more companies to explore sustainable methods.

Young designers are spearheading the trend, which remains a niche within a sector that was worth an estimated 2.4 billion euros ($2.7 billion) in France alone last year.

"As a consumer, I did not find a brand that offered sexy outfits that were completely responsible along the entire production chain," explains Margot Dargegen, 25, who founded Nenes Paris with recycled lace a year ago.

"Scraps of fabric and plastic bottles are ground up and turned into fibres that become thread that you can then make the material you want to from," she adds.

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"When we started out, finding eco-friendly materials was harder, but we see now that things are starting to move," says Mathilde de Sacy, 28, who created the Olly brand with a friend three years ago.

"We use certified material, organic GOTS cotton, lace made with recycled fibres and Oeko-Tex 100 dyes. We also wanted the work to be done in Europe to ensure proper working conditions," she adds.

"Consumers pay more and more attention to such things," notes Cecile Vivier-Guerin, marketing director for a lingerie show in Paris.

In particular, suppliers are offering wider ranges of fabrics that respect the environment, she said.

They include classic recycled cotton, or satin, or bra shells made from coffee fibre.

A Swiss company offers a line of lingerie that is completely biodegradable.

In a sector that has stagnated in recent years, "it encourages consumers to buy better quality products that require less transport and add value," Vivier-Guerin said.

"It's a significant stimulus," she noted.

National brands such as Etam have taken note, and now offer collections made from recycled lace as well.

"Everyone understands that it is an important factor consumers look for," says Gildas Minvielle, head of the Economic Observatory at the French Fashion Institute.

That said, "100 percent ecological is hard to attain," admitted Casile, who emphasises that brands interested in the idea must go beyond the purely marketing aspect.

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Nestle to invest 2bn Swiss francs in recycled plastics
Geneva (AFP) Jan 16, 2020
Swiss food giant Nestle said Thursday it would invest 2.0 billion Swiss francs (1.8 billion euros, $2.1 billion) over five years to cut its use of virgin plastics in favour of food-grade recycled plastics. The company, whose brands include Nespresso coffee, Vittel water and Smarties chocolates, also plans to invest in new types of sustainable packaging to meet its target of making all packaging recyclable or reusable by 2025. Nestle also said in a statement that it would reduce its use of virgin ... read more