New insights into the polymer mystique for conducting charges

Article in Journal of Applied Physics describes how electrical charges may leak through a labyrinth of molecules

2013-08-09

(Press-News.org) WASHINGTON D.C. August 9, 2013 -- For most of us, a modern lifestyle without polymers is unthinkable…if only we knew what they were. The ordinary hardware-store terms we use for them include "plastics, polyethylene, epoxy resins, paints, adhesives, rubber" -- without ever recognizing the physical and chemical structures shared by this highly varied -- and talented -- family of engineering materials.

Polymers increasingly form key components of electronic devices, too -- and with its ever-escalating pursuit of high efficiency and low cost, the electronics industry prizes understanding specific behaviors of polymers. The ability of polymers to conduct charge and transport energy is especially appealing.

Now there's help in appreciating the polymer mystique related to the emerging field of molecular conduction in which films of charge-transporting large molecules and polymers are used within electronic devices. These include small-scale applications such as light emitting diodes (LED). At the other end of the scale, in cities and across oceans, the polymer polyethylene is the vital insulating component in the reliable and safe transport of electrical energy by high voltage underground cables.

In work appearing in the current edition of the Journal of Applied Physics, researchers at the United Kingdom's Bangor University describes how electrical charges may leak away to the ground through its labyrinth of molecules.

Researchers Thomas J. Lewis and John P. Llewellyn pay particular attention to the nano-scale structure of polyethylene in which crystalline regions are separated by areas known as "amorphous zones." Their novel employment of superexchange and quantum mechanical tunneling of electrons through the amorphous parts of the polymer helps improve understanding of electrical charge conduction.

"These findings could lead not only to improved properties of high voltage cables but also to a wider understanding of polymer semiconductors in device applications," said Lewis.

Their investigation shows that the tunneling feature accounts for the majority of the reported high-field charge transport effects in polyethylene.

### The article, "Electrical conduction in polyethylene: The role of positive charge and the formation of positive packets" is authored by Thomas J. Lewis and John P. Llewellyn. It appears in the Journal of Applied Physics. See: http://dx.doi.org/10.1063/1.4810857

ABOUT THE JOURNAL The Journal of Applied Physics, published by AIP Publishing, is an influential international journal featuring significant new experimental and theoretical results of applied physics research. See http://jap.aip.org

ELSE PRESS RELEASES FROM THIS DATE:

Cells eat themselves into shape

2013-08-09

The process cells use to 'swallow' up nutrients, hormones and other signals from their environment – called endocytosis – can play a crucial role in shaping the cells themselves, scientists at the European Molecular Biology Laboratory (EMBL) in Heidelberg, Germany, have found. The study, published today in Nature Communications, could help explain how the cells on your skin become different from those that line your stomach or intestine. "We're the first to show that endocytosis really drives changes in cell shape by directly remodelling the cell membrane," says Stefano ...

The 'genetics of sand' may shed new light on evolutionary process over millions of years

2013-08-09

An evolutionary ecologist at the University of Southampton, is using 'grains of sand' to understand more about the process of evolution. Dr Thomas Ezard is using the fossils of microscopic aquatic creatures called planktonic foraminifera, often less than a millimetre in size, which can be found in all of the world's oceans. The remains of their shells now resemble grains of sand to the naked eye and date back hundreds of millions of years. A new paper by Dr Ezard, published today (9 August 2013) in the journal Methods in Ecology & Evolution, opens the debate on the best ...

How to achieve a well-balanced gut

2013-08-09

Creating an environment that nurtures the trillions of beneficial microbes in our gut and, at the same time, protects us against invasion by food-borne pathogens is a challenge. A study published on August 8 in PLOS Pathogens reveals the role of a key player in this balancing act. SIGIRR is a protein present at the surface of the cells that line the gut that dampens the innate (non-specific) immune response of these cells to bacteria. The new study, led by Xiaoxia Li (from the Lerner Research Institute in Cleveland, USA) and Bruce Vallance (from BC's Childrens' Hospital ...

Dialysis patients may live longer if their kidney specialist sees fewer patients

2013-08-09

Nephrologists whose dialysis patients had the best survival over six years had a significantly lower patient caseload than nephrologists whose patients had the worst survival. For every additional 50 patients cared for by a nephrologist, patients had a 2% higher risk of dying within six years. Worldwide, more than 1.5 million people are treated with hemodialysis. Washington, DC (August 8, 2013) — Dialysis patients receiving treatment from kidney specialists with a higher patient caseload have a greater risk of dying prematurely than those receiving care from specialists ...

JILA researchers discover atomic clock can simulate quantum magnetism

2013-08-09

Researchers at JILA have for the first time used an atomic clock as a quantum simulator, mimicking the behavior of a different, more complex quantum system.* Atomic clocks now join a growing list of physical systems that can be used for modeling and perhaps eventually explaining the quantum mechanical behavior of exotic materials such as high-temperature superconductors, which conduct electricity without resistance. All but the smallest, most trivial quantum systems are too complicated to simulate on classical computers, hence the interest in quantum simulators. Sharing ...

Telemedicine consultations significantly improve pediatric care in rural emergency rooms

2013-08-09

Telemedicine consultations with pediatric critical-care medicine physicians significantly improve the quality of care for seriously ill and injured children treated in remote rural emergency rooms, where pediatricians and pediatric specialists are scarce, a study by researchers at UC Davis Children's Hospital has found. The study also found that rural emergency room physicians are more likely to adjust their pediatric patients' diagnoses and course of treatment after a live, interactive videoconference with a specialist. Parents' satisfaction and perception of the quality ...

Study reveals role of 'peacekeeper' in the gut

2013-08-09

A new study has shone a spotlight on the peacekeeping mechanisms in our intestines. A protein, called SIGIRR, is produced by the cells that line the intestines. It supresses the cells' immune response to bacteria. "We expected that when SIGIRR was removed, our intestines would trigger a stronger immune response to a gut infection, affording us more protection against the infection," says Prof. Bruce Vallance, an associate professor in UBC's Dept. of Pediatrics and a scientist at the Child & Family Research Institute at BC Children's Hospital. "Instead, the stronger ...

Autism affects different parts of the brain in women and men

2013-08-09

Autism affects different parts of the brain in females with autism than males with autism, a new study reveals. The research is published today in the journal Brain as an open-access article. Scientists at the Autism Research Centre at the University of Cambridge used magnetic resonance imaging to examine whether autism affects the brain of males and females in a similar or different way. They found that the anatomy of the brain of someone with autism substantially depends on whether an individual is male or female, with brain areas that were atypical in adult females ...

Muscle health depends on sugar superstructure

2013-08-09

For many inherited diseases, such as cystic fibrosis or Huntington disease, the disease-causing genetic mutation damages or removes a protein that has an essential role in the body. This protein defect is the root cause of the disease symptoms. However, for a group of muscular dystrophies known collectively as congenital muscular dystrophies (CMDs), the sequence of the protein that is central to normal function is typically unaffected. Instead, the defects lie in processing proteins—ones that are responsible for modifying the central protein by adding sugar chains (glycans). ...

Views you can use? How online ratings affect your judgment

2013-08-09

CAMBRIDGE, MA -- Are you influenced by the opinions of other people — say, in the comments sections of websites? If your answer is no, here's another question: Are you sure? A new study co-authored by an MIT professor suggests that many people are, in fact, heavily influenced by the positive opinions other people express online — but are much less swayed by negative opinions posted in the same venues. Certain topics, including politics, see much more of this "herding" effect than others. The results, published today in the journal Science, detail a five-month experiment ...

NFCR congratulates Dr. Robert C. Bast, Jr. on receiving the AACR-Daniel D. Von Hoff Award for Outstanding Contributions to Education and Training in Cancer Research

New insights into the polymer mystique for conducting charges

ELSE PRESS RELEASES FROM THIS DATE:

LAST 30 PRESS RELEASES: