Polyethylene, an inexpensive commodity plastic, has been successfully used by researchers to synthesize the “ideal” polymer nanocrystal. Normally, this plastic is only partly crystalline, but a new catalyst has produced material that eliminates amorphous structures. The crystalline nanostructure could prove of interest to production of new kinds of coatings.
Polymer, or plastic, solar cells contain Earth-abundant and environmentally benign materials, can be made flexible and lightweight, and can be fabricated using roll-to-roll technologies. But the cells’ power-conversion efficiency has been limited. A Northwestern Univ. research reports the design and synthesis of new polymer semiconductors a plastic solar cells with fill factors of 80%. This number is close to that of silicon solar cells.
A team of chemists at Syracuse Univ. has used a temperature-sensitive polymer to regulate DNA interactions in both a DNA-mediated assembly system and a DNA-encoded drug-delivery system. Their findings may improve how nanomaterials self-assemble into functional devices and how anticancer drugs, including doxorubicin, are delivered into the body.
A new cost-effective polymer membrane can decrease the cost of alkaline batteries and fuel cells by allowing the replacement of expensive platinum catalysts without sacrificing important aspects of performance, according to Penn State Univ. researchers.
Scientists have spent decades trying to build flexible plastic solar cells efficient enough to compete with conventional cells made of silicon. To boost performance, research groups have tried creating new plastic materials that enhance the flow of electricity through the solar cell. Recently, scientists discovered that disorder at the molecular level actually improves the polymers' performance.
Some animals, like the octopus and cuttlefish, transform their shape based on environment. For decades, researchers have worked toward mimicking similar biological responses in non-living organisms, as it would have significant implications in the medical arena. Now, researchers at the Univ. of Pittsburgh have demonstrated such a biomimetic response using hydrogels.
Ethylene, now produced from petroleum, is one of the most important raw materials for everyday products. Researchers in China say they have identified a promising alternative to petroleum. Their proposal, a fluidized bed reactor, works by suspending the chemicals needed to make ethylene inside the walls of a chamber. Newly produced ethylene exits through a pipe, while the rest of the material remains to continue production.
Fluorescent tetrapod nanocrystals could light the way to the future design of stronger polymer nanocomposites. A team of researchers with Lawrence Berkeley National Laboratory has developed an advanced optomechanical sensing technique based on tetrapod quantum dots that allows precise measurement of the tensile strength of polymer fibers with minimal impact on the fiber’s mechanical properties.
Scientists are working to reduce the nation's reliance on fossil fuels by developing environmentally friendly and cost effective plastics from natural, sustainable and renewable materials, such as vegetable oils, starches, sugars—even recycled grass clippings. The Univ. of Minnesota’s Center for Sustainable Polymers has recruited more than 25 companies to help develop new materials and those already on the market, like polylactide.
Researchers from North Carolina State Univ. have developed more accurate measurements of how efficiently a polymer called MEH-PPV amplifies light, which should advance efforts to develop a new generation of lasers and photonic devices. MEH-PPV is a low-cost polymer that can be integrated with silicon chips, and researchers have sought to use the material to convert electricity into laser light for use in photonic devices.
Researchers in South Korea have reported the development of a new plasmonic material that can be applied to both polymer light-emitting diodes (PLEDs) and polymer solar cells (PSCs), resulting in high performance from a low-cost fabrication process. They say the material is easy to synthesize with basic equipment and has low-temperature solution processability.
Until now, polymers with temperature-controlled shape memory could only change form once. Biomaterial researchers have recently developed plastics that can repeatedly change from one shape to another and then back again when temperatures fluctuate within a selected range. The material is dubbed “polymer actuators” by its creators in Germany.
Today’s options for high-performance fibers, include Kevlar, Spectra, Dyneema and Zylon. They have been the strongest synthetics in the world. But Marilyn Minus, an asst. prof. of engineering at Northeastern Univ., has developed a type of fiber that is stronger than the first three commercial products mentioned above, and in its first generation approaches the strength of Zylon.
Introductory chemistry students learn that oil and water repel each other. So do other hydrophobic substances, which carry no electric charge, and hydrophilic substances, which carry an electric charge that allows them to mix with water. In a recent study, a group of bioengineers have found a way to strongly adhere hydrogels to hydrophobic silicone substrates, an innovation that provides a valuable new tool for microscale biotechnology.
Designers of buildings typically have no choice but to use black or bluish-gray colored solar panels. With the help of thin-film technologies, however, researchers in Germany have now added color to solar cells. Optics specialists have changed physical thickness of the transparent conductive oxide layer, modifying its refractive index.
In a new study, a “bioadhesive” coating developed at Brown Univ. significantly improved the intestinal absorption into the bloodstream of nanoparticles that someday could carry protein drugs such as insulin. Such a step is necessary for drugs taken by mouth, rather than injected directly into the blood.
Electrolysis is often used to produce hydrogen that can be used for a storable fuel. Modified solar cells with highly efficient architecture can use this method to obtain hydrogen from water with the help of catalysts. But these solar cells rapidly corrode in aqueous electrolytes. By embedding the catalysts in an electrically conducting polymer, researchers have prevented this corrosion while maintaining competitive efficiency.
Sandia National Laboratories researchers want airports, border checkpoints and others to detect homemade explosives made with hydrogen peroxide without nabbing people whose toothpaste happens to contain peroxide. That’s part of the challenge faced in developing a portable sensor to detect a common homemade explosive called a FOx mixture, made by mixing hydrogen peroxide with fuels.
Space scientists from the Univ. of New Hampshire and the Southwest Research Institute report that data gathered by NASA’s Lunar Reconnaissance Orbiter show lighter materials like plastics provide effective shielding against the radiation hazards faced by astronauts during extended space travel. The finding could help reduce health risks to humans on future missions into deep space.
Using star-shaped block co-polymer structures as tiny reaction vessels, researchers have developed an improved technique for producing nanocrystals with consistent sizes, compositions and architectures—including metallic, ferroelectric, magnetic, semiconductor and luminescent nanocrystals. The technique relies on the length of polymer molecules and the ratio of two solvents to control the size and uniformity of colloidal nanocrystals.
Rice Univ. researchers have for the first time detailed the molecular mechanism that makes a particular combination of cement and polymer glue so tough. The theoretical research led to a fine picture of how hydrogen bonds control the properties of hybrid organic-inorganic materials. The finding has implications for understanding the interface bonding that is often a roadblock to improved composite properties.
Are teeth the latest victims of bisphenol A (BPA)? Yes, according to the conclusions of a team lead by researchers in France. They have shown that the teeth of rats treated with low daily doses of BPA could be damaged the chemical.
The potential energy available via solar power might seem limitless on a sunny summer day, but all that energy has to be stored for it to be truly useful. If you see a solar panel on a rooftop, a bulky battery or supercapacitor is hidden just out of sight, receiving energy from the panel through power lines. However, that's a storage method that doesn't scale well for solar-powered devices with no space for a battery pack.
A chemical that’s often the key ingredient in improvised explosive devices can be quickly and safely detected in trace amounts by a new polymer created by a team of Cornell Univ. chemists. The polymer, which potentially could be used in low-cost, handheld explosive detectors and could supplement or replace bomb-sniffing dogs, was invented in the lab of William Dichtel, assistant professor of chemistry and chemical biology.
A rabbit sculpture, the size of a typical bacterium, is one of several whimsical shapes created by a team of Japanese scientists using a new material that can be molded into complex, highly conductive 3D structures with features just a few micrometers across. The new resin holds promise for making customized electrodes for fuel cells or batteries, as well as biosensor interfaces for medical uses.