ChemWeb Newsletter

Not a subscriber? Join now.March 8, 2005


In The Alchemist this issue, collapsing bubbles hotter than the stars, unraveling a cellulose mystery, and rolling up e-paper. Also in the latest issue: turning garbage gas into something useful and the boron aggregates that cluster together at last.

The idea of sustainable and useful desktop fusion remains a controversial field, but studies into related laboratory effects continue. Now, Ken Suslick and David Flannigan of the University of Illinois at Urbana-Champaign have demonstrated that the temperature inside a collapsing sonoluminescent bubble is four times the temperature of the surface of the sun. "When bubbles in a liquid get compressed, the insides get hot - very hot," explains Suslick, but until now nobody has measured this temperature. Sonoluminescence arises from acoustic cavitation when small gas bubbles in a liquid are "irradiated" with sound waves above 18 kHz. As the bubbles collapse intense local heating occurs, which produces light. Suslick and Flannigan observed the spectra of the light, which reveals the bubble's incredibly high temperature, and suggest that such temperatures could only arise from a plasma.

UK researchers reveal that the ability to digest cellulose, the most common organic material produced by life, is not such a rare talent in the animal kingdom as scientists previously thought. Angus Davison of the University of Nottingham and Mark Blaxter of the University of Edinburgh were aware that a few animals possess cellulase enzymes, which is capable of breaking down the tough sugar-based polymers produced by plants. However, scientists were puzzled as to why an enzyme hundreds of millions of years old should not be more widespread in the animal kingdom. After all, cellulose would make a ready fuel source for any organism if it could be broken down. Now, the researchers have discovered that cellulases are not so rare after all, turning up in earthworms, sea urchins, lobsters, and bees. The researchers suggest that our ancient evolutionary ancestors may also have had cellulase enzymes, although why we lost them remains a mystery.

A polymer-based display developed by Dutch company Philips under the PolymerVision brand, can be rolled up like a newspaper. The PolymerVision PV-QML5 announced on March 2 is an ultra-thin (100µm) featherweight 320 x 240 pixel active-matrix display, five inches from corner to corner. Each layer of the matrix is flexible allowing the whole sheet to be rolled up. While flexible plastic displays have been discussed for several decades, this device is perhaps the first to become a commercial reality. According to Philips, it generates four shades of gray and can be read under almost any light conditions, even sunlight, as though it were real newsprint, but with the obvious advantage that the contents can be changed.

Methane from garbage dumps and landfill sites could be converted into useful fuel more effectively, according to Viktor Popov of the Wessex Institute of Technology, in Southampton, UK. Popov has developed a solution to the problem of air getting into the methane during extraction of the gas from landfills. The solution could make extraction from even small sites economically viable. The solution uses on three-layer membrane based on clay to cover a landfill site. Carbon dioxide is pumped into the semi-permeable layer which then acts as a pressurized barrier to the outside, preventing air from being drawn into the landfill as the methane is pumped out. The next step in the development of the idea will be to find a way to remove the nitrogen from the extracted methane.

Inorganic clusters bridge the gap between molecular chemistry and solid state chemistry. Now, John Kennedy and colleagues from the University of Leeds and CLRC Daresbury have investigated the cluster chemistry of boron hydrides in the hope of extending the chemistry of this intriguing class of compounds beyond the well-worn stable region of clusters containing just twelve boron atoms. They report two macropolyhedral metalloborane complexes containing 14 and 16 boron atoms, which form through a chemical fusion-condensation process. The researchers say this is an important step towards developing boron chemistry and sheds light on how other boron fragments might be aggregated.