Nano-flowers for alcohol detection
Spectacular flower-like nanostructures grown in a laboratory in China can detect alcohol and might also be useful as catalysts.The "nanoflowers" were made from zinc oxide by Yujin Chen and colleagues at Harbin Engineering University. Conventional sensors look set to be replaced by a new generation of detectors. "Zinc oxide sensors need to be heated to temperatures of up to300°C before they become sensitive to ethanol. Chen's nanoflowers become sensitive at just 140°C.The observation of ultra-high sensitivity for ethanol at such an unusually low temperature is striking. The new operating temperature is low enough to be practical to be built in solid state sensors such as lab-on-a chip devices.The advantage of nanostructures is that they are more compact and use less power than conventional ones. Nanosensors consume just nanowatts of power, while those on a larger scale can use milliwatts. Zinc oxide changes resistance when molecules of ethanol vapour stick onto it in a process called adsorption. The flower-like structures work at lower temperatures because their tiny size enhances adsorption. Each flower is made up of bundles of nanorods 15nm wide. They were made by blasting a zinc-containing solution with ultrasound.
Source: newscientisttech.comAdded: 15 March 2007