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Building ‘OLEDs’ from the ground up for better electronics

From smartphones to TVs and laptops, light emitting diode (LED) displays are ubiquitous. OLEDs (where the O denotes they are organic, or carbon-based) are among the most energy efficient of these devices, but they generally have higher production costs due to the laborious fabrication processes needed to arrange them properly. Today in ACS Central Science, researchers introduce a new way to efficiently create patterns of OLEDs.

In an LED display, the emissions from red, green and blue diodes are blended to create the white and colored light necessary to render images. It is crucially important to precisely position the different types of diodes in relation to one another. And although many fabrication methods exist, they all have limitations with regard to scalability, pattern control, or feature resolution. Solution-based protocols are attractive because they are inexpensive and well-suited to large scale manufacturing. However, current techniques do not meet the demands required for commercial OLED display technology. Zak Page, Craig Hawker and colleagues at the University of California, Santa Barbara and the Dow Chemical Company sought to overcome this barrier by adopting a bottom-up approach for patterning emissive polymers.

By American Chemical Society - Thursday, June 8, 2017 - Full Story

Turning car plastics into foams with coconut oil

End-of-life vehicles, with their plastic, metal and rubber components, are responsible for millions of tons of waste around the world each year. Now, one team reports in ACS Sustainable Chemistry & Engineering that the plastic components in these vehicles can be recycled with coconut oil and re-used as foams for the construction, packaging and automotive industries.

Recycled polycarbonate (PC) and polyurethane (PUR) are ideal for building insulation, refrigerators, cushions and packaging products. But it can be challenging for plastic car components to get to that point. Some plastic wastes from vehicles can be easily reprocessed; however, PC and PUR materials require a more arduous chemical recycling method. In addition, paints and coatings on PC and PUR plastics from cars typically interfere with the process, causing the recycled product to deteriorate. And simply adding some types of recycled PC and PUR materials to existing insulation foams, for example, can make the foams too dense or brittle. Although researchers have developed various chemical recycling techniques, very few have tried to make useable products with them. Hynek Beneš, Aleksander Prociak and colleagues wanted to take a new approach to converting PC and PUR into recycled materials, with the hopes of increasing their applications.

By American Chemical Society - Thursday, June 8, 2017 - Full Story

Chemistry life hacks: Food edition (video)

WASHINGTON — Reactions is back with another round of chemistry life hacks. Our latest episode brings chemistry to the kitchen, and features science-backed tips to cook rice with fewer calories, get extra juicy chicken (when you don’t have time to marinate) and keep sliced fruit from browning too quickly. Watch the video and find out how to use chemistry to give your food a flavor boost.

 

By American Chemical Society - Wednesday, June 7, 2017 - Full Story

Searching beyond graphene for new wonder materials

Graphene, the two-dimensional, ultra lightweight and super-strong carbon film, has been hailed as a wonder material since its discovery in 2004. Now researchers are going beyond graphene and preparing other 2-D films with extraordinary properties for applications in wearable electronics, sensors and energy storage. The cover story in Chemical & Engineering News (C&EN), the weekly newsmagazine of the American Chemical Society, surveys this expanding landscape.

Mitch Jacoby, a senior correspondent at C&EN, notes that most 2-D materials have certain features in common: They tend to be flexible, transparent, and can be tuned more easily than their bulk counterparts. Some are electrical conductors, and others are insulators or semiconductors. However, there are some gray areas about what 2-D means. How many layers thick can they be? Do the materials need to be free standing?

While those questions are not fully resolved, researchers have forged ahead with the creation of new ultrathin films with varying properties. They largely fall into five major groups: MXenes, Xenes, organic materials, transition metal dichalcogenides and nitrides. The materials are in differing stages of development, from laboratory curiosity to demonstration devices.

2-D materials go beyond graphene

By American Chemical Society - Saturday, June 3, 2017 - Full Story

How the Nazis invented nerve agents like sarin (video)

WASHINGTON — Nerve agents are arguably the most brutal chemical weapons. These infamous compounds, which include sarin gas and VX, originated in Nazi Germany when a chemist was trying to develop a more effective insecticide. Marrying the element phosphorus with cyanide derivatives resulted in a poison so deadly it was named “Tabun,” derived from the German word for “taboo.”

By American Chemical Society - Thursday, June 1, 2017 - Full Story

What bone proteomics could reveal about the dead

Studying bones has helped scientists reconstruct what dinosaurs and other extinct creatures looked like. Taking this further, scientists recently started identifying proteins from bones to glean more information about remains. But one team has found that the reliability of this approach can depend on which bone is analyzed. Additionally, they report in ACS’ Journal of Proteome Research a forensic use for bone proteomics: potentially determining from bone proteins how old someone was when they died.

By American Chemical Society - Tuesday, May 30, 2017 - Full Story

Sorghum: health food, sweetener and now, clothing dye

Sorghum has long been a staple food in many parts of the world, but in the U.S., it’s best known as a sweetener and livestock feed. As demand for the grain soars, so does the amount of waste husks. To reduce this waste, scientists report in the journal ACS Sustainable Chemistry & Engineering a new use for it: a wool dye that can add ultraviolet protection and fluorescence properties to clothing.

Sorghum, which looks like pearl couscous, is a hardy, drought-tolerant crop that is gaining popularity as a health food, livestock feed and source of bioethanol. Additionally, scientists are working on transforming the crop’s waste for a range of applications, including food coloring and waste water purification. Building further on the colorant possibilities, Yiqi Yang, Xiuliang Hou and colleagues wanted to see if they could develop a practical clothing dye out of sorghum husks.

By American Chemical Society - Wednesday, May 24, 2017 - Full Story

Should you pee on a jellyfish sting? (video)

WASHINGTON — Sure, jellyfish look pretty serene, but we all know the evils that come from a run-in with those tentacles. You’ve probably heard the rumor that peeing on a jellyfish sting can make the pain go away, but does this icky old wives tale stand up to science? Filmed at San Francisco’s Aquarium of the Bay, the latest Reactions episode explains the fearsome chemistry of jellyfish stings, and debunks this age-old beach myth.

By American Chemical Society - Tuesday, May 23, 2017 - Full Story

Conductive paper could enable future flexible electronics

Roll-up computer screens and other flexible electronics are getting closer to reality as scientists improve upon a growing number of components that can bend and stretch. One team now reports in the journal ACS Applied Materials & Interfaces another development that can contribute to this evolution: a low-cost conductive paper that would be easy to manufacture on a large scale.

Current flexible electronic prototypes are commonly built using polymer thin films. But the cost of these films becomes a factor when they are scaled up. To address this issue, scientists have turned to paper, which is renewable, biodegradable and a fraction of the cost of polymer thin films. The downside of paper is that it’s not conductive, and efforts so far to infuse it with this property have been hindered by scalability and expense. Bin Su, Junfei Tian and colleagues wanted to come up with a new approach.

Using a conventional roller process that’s easy to scale up, the researchers coated paper with soft ionic gels to make it conductive. They sandwiched an emissive film between two layers of the ionic gel paper. When they applied a voltage, the device glowed blue, indicating that electricity was being conducted. It also showed electrical durability, withstanding more than 5,000 cycles of bending and unbending with negligible changes in performance and lasting for more than two months. The researchers say their conductive paper, which costs about $1.30 per square meter and could be fabricated at a rate of 30 meters per minute, could become an integral part of future flexible electronics.

Ionic Gel Paper with Long-Term Bendable Electrical Robustness for Use in Flexible Electroluminescent Devices

By American Chemical Society - Sunday, May 21, 2017 - Full Story

Top Bose SoundTouch a worthy successor to the SoundDock 10

Big sound from a small box, with enough connectivity to please nearly everyone. That’s what Bose’s SoundTouch line of speakers offers, and the flagship of the series is a remarkable unit, indeed.

SoundTouch products have been out for a few of years now; I first experienced them at their introduction in New York back in 2013, and such is their quality and design that they’re still on the market today. That’s unlike the remarkable SoundDock 10 iPod dock speaker system that was my first “modern” experience with Bose - modern meaning within the last 10 years, since Bose itself has been around for more than a half century.

I remember Bose’ SoundDock 10 introductory demo well. The company had set one up behind a Wizard of Oz-like curtain in a private room in a Manhattan restaurant and kicked off the demo with some really great-sounding rumbling thunder. I said then that the demo came “complete with bone rattling realism that sounded as if it were coming from an ‘honest to goodness’ audio system with big speakers and big amplifier power.”


How GMOs are regulated… or not—Speaking of Chemistry

By American Chemical Society - Thursday, May 18, 2017 - Full Story

When water levitates (video)

WASHINGTON — Have you ever seen a drop of water navigate a maze? It’s possible thanks to the same phenomenon that lets you know if a griddle is hot enough for pancake batter. Water droplets that dance and skitter across a hot surface instead of boil away on the spot are experiencing the Leidenfrost effect. Understanding Leidenfrost — first described more than 200 years ago — helped engineers make more efficient steam engines. Today, scientists are using high-speed cameras to better characterize how superhot water behaves on metal surfaces. The investigation might lead to improvements in power generation. Watch the superhot dancing droplets here: https://youtu.be/9tlIWlGvkRc.

By News on the Net - Tuesday, May 16, 2017 - Full Story

Your Condo on the Moon

Colonizing the Moon has been claimed to be the stepping stone for colonizing planet Mars (NASA: “En Route to Mars”). Some folks are all in favor, with headlines like “Make American First on the Moon again!

Even the renowned astrophysicist Stephen Hawking has been adamant in his doom scenario projections: In one hundred year or so, mankind can no longer live on earth. That’s a big “upgrade” from “... one thousand years ...” that Hawking made just a few months ago. No wonder then, the (renewed) race to the moon and planets (not limited to Mars) is just getting underway.

By Dr. Klaus L.E. Kaiser - Saturday, May 13, 2017 - Full Story

‘Heroes of Chemistry’ improve people’s lives through the transforming power of chemistry

WASHINGTON — Scientists who developed products that have led to significant advancements in human health, technology, the food supply, and the environment, will be inducted into a scientific “Hall of Fame” later this summer, becoming the newest Heroes of Chemistry, an honor bestowed by the American Chemical Society (ACS), the world’s largest scientific society.

By American Chemical Society - Tuesday, May 9, 2017 - Full Story

‘Lab-on-a-glove’ could bring nerve-agent detection to a wearer’s fingertips (video)

There’s a reason why farmers wear protective gear when applying organophosphate pesticides. The substances are very effective at getting rid of unwanted bugs, but they can also make people sick. Related compounds — organophosphate nerve agents — can be used as deadly weapons. Now researchers have developed a fast way to detect the presence of such compounds in the field using a disposable “lab-on-a-glove.” The report on the glove appears in the journal ACS Sensors.

Organophosphate nerve agents, including sarin and VX, are highly toxic and can prevent the nervous system from working properly. Organophosphate pesticides are far less potent but work in a similar way and can cause illness in people who are exposed to them, according to the U.S. Centers for Disease Control and Prevention. Detecting either type of these sets of compounds accurately and quickly could help improve both defense and food security measures. So, Joseph Wang and colleagues set out to develop a wearable sensor that could meet the requirements of field detection.

By American Chemical Society - Friday, May 5, 2017 - Full Story

LG OLED TV a true game changer for home theatres

The quest for the best TV picture possible has been a long one, stretching back to the early days of cathode ray tubes and muddy black and white pictures on small and, compared with even the worst of today’s TV’s, grainy screens.

Then we had colour and, decades later, high definition, both of which were game changers. The next game changer was the evolution from big, fat and heavy CRT’s to liquid crystal, or LCD – the flat screens that have freed up space in our viewing rooms while also offering us better quality and larger pictures. LCD evolved to LED, which are really LCD panels with different "back lighting."

Now there are two new technologies vying for your after tax dollars, one of which is a logical next step  in the high definition evolution – 4K – and one of which is an absolutely ground breaking leap in picture technology: OLED.


The chemistry of whiskey

WASHINGTON — Derby Day is around the corner, and with it comes big hats, horses with funny names, and bourbon. The latest episode of Reactions celebrates the chemical process of distillation that makes bourbon and other whiskey varieties possible. Since water and ethanol, along with tasty flavors, have different boiling points, they can be separated by carefully heating the mash that starts off every whiskey. Each distillery carefully protects their still design, engineered to create their signature liquor. The strongest flavors take aging, but might some innovative whiskey makers find a way to hack maturation time? There’s a barrel-full of chemistry in this video about whiskey.

By American Chemical Society - Tuesday, May 2, 2017 - Full Story

Toward a safer permanent hair dye that mimics melanin

Coloring hair has become a common practice, particularly for people who want to hide their graying locks. But an ingredient in many of today’s commercial hair dyes has been linked to allergic reactions and skin irritation. Now scientists have developed a potentially safer alternative by mimicking the hair’s natural color molecule: melanin. Their report appears in the journal ACS Biomaterials Science & Engineering.

The permanent hair dye ingredient p-phenylenediamine (PPD) has been associated, although rarely, with allergic reactions including facial swelling and rashes. Coloring hair with natural melanin would be an intuitive alternative to PPD. But previous research has found that the pigment molecules clump together, forming rods and spheres too large to penetrate into the hair shaft to create lasting color. Jong-Rok Jeon and colleagues wanted to build on the idea of using melanin but with a molecule that mimics the real thing.

The researchers turned to polydopamine, a black substance that is structurally similar to melanin and has been explored for use in a variety of biomedical applications. Polydopamine with iron ions transformed gray hairs into black and lasted through three wash cycles. Lighter shades could also be achieved with polydopamine by pairing it with copper and aluminum ions. And toxicity tests showed that mice treated with the colorant didn’t have noticeable side effects, while those that received a PPD-based dye developed bald spots.

Read More…”Metal-Chelation-Assisted Deposition of Polydopamine on Human Hair: A Ready-to-Use Eumelanin-Based Hair Dyeing Methodology

By American Chemical Society - Sunday, April 30, 2017 - Full Story

Art of paper-cutting inspires self-charging paper device

Despite the many advances in portable electronic devices, one thing remains constant: the need to plug them into a wall socket to recharge. Now researchers, reporting in the journal ACS Nano, have developed a light-weight, paper-based device inspired by the Chinese and Japanese arts of paper-cutting that can harvest and store energy from body movements.

Portable electronic devices, such as watches, hearing aids and heart monitors, often require only a little energy. They usually get that power from conventional rechargeable batteries. But Zhong Lin Wang, Chenguo Hu and colleagues wanted to see if they could untether our small energy needs from the wall socket by harvesting energy from a user’s body movements. Wang and others have been working on this approach in recent years, creating triboelectric nanogenerators (TENGs) that can harness the mechanical energy all around us, such as that created by our footsteps, and then use it to power portable electronics. But most TENG devices take several hours to charge small electronics, such as a sensor, and they’re made of acrylic, which is heavy.

So the researchers turned to an ultra-light, rhombic paper-cut design a few inches long and covered it with different materials to turn it into a power unit. The four outer sides, made of gold- and graphite-coated sand paper, comprised the device’s energy-storing supercapacitor element. The inner surfaces, made of paper and coated in gold and a fluorinated ethylene propylene film, comprised the TENG energy harvester. Pressing and releasing it over just a few minutes charged the device to 1 volt, which was enough to power a remote control, temperature sensor or a watch.


Read more…”Ultralight Cut-Paper-Based Self-Charging Power Unit for Self-Powered Portable Electronic and Medical Systems

By American Chemical Society - Sunday, April 30, 2017 - Full Story

Synthetic two-sided gecko’s foot could enable underwater robotics

Geckos are well known for effortlessly scrambling up walls and upside down across ceilings. Even in slippery rain forests, the lizards maintain their grip. Now scientists have created a double-sided adhesive that copies this reversible ability to stick and unstick to surfaces even in wet conditions. They say their development, reported in ACS’ Journal of Physical Chemistry C, could be useful in underwater robotics, sensors and other bionic devices.

By American Chemical Society - Thursday, April 27, 2017 - Full Story