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NANOSCALE CHEMICAL SENSORS
23 August 2004 - University of California, Davis
| New types of chemical sensors for environmental monitoring, food safety or security applications could be based on nanotechnology. |
New types of chemical sensors for environmental monitoring, food safety or security applications could be based on nanotechnology, according to Frank Osterloh, an assistant professor of chemistry at UC Davis. 'Nanomaterials are very well suited for chemical sensor applications, because their physical properties often vary considerably in response to changes of the chemical environment,' Osterloh said. Because nanomaterials can be made up of structures just a few atoms across, just a few molecules of chemical can trigger a response, he said. Osterloh, with graduate student Xiubin Qi and former student Jason Martino, discovered that nanowires made of lithium, molybdenum and selenium atoms show changes in electrical resistance of up to 200 percent when exposed to vapours of organic solvents. By depositing the nanowires between two conductors, they made a simple chemical sensor. By attaching chemical groups to the nanowires, the researchers could modify the sensor to measure the acidity of a solution. The team is now investigating if this 'programming' property can be extended to make sensors for the detection of explosives or environmental contaminants such as lead in drinking water, Osterloh said. The work was presented at the 228th national meeting of the American Chemical Society in Philadelphia, 22-26 August 2004.
Osterloh's laboratory is also experimenting with nanoscale chemical sensors based on materials that change color; nanomaterials that can be manipulated in magnetic fields; and luminescent materials.
http://www.ucdavis.edu
About: University of California, Davis
Set between the Coast Range to the west and the towering Sierra Nevada to the east in the heart of the Central Valley, UC Davis is close to California’s thriving state capital and the San Francisco Bay Area UC Davis is one of 10 campuses of the University of California, which was chartered as a land grant college in 1868 and now constitutes the pre-eminent system of public higher education in the country. Together, the 10 campuses have an enrollment of some 173,000 students, 90 percent of them California residents. Some 150 laboratories, extension centers, research and field stations strengthen teaching and research while providing public service to California and the nation. The collections of the more than 100 UC campus libraries are surpassed in size in the United States only by that of the Library of Congress. The Davis campus has undergraduate colleges of Agricultural and Environmental Sciences, Engineering, and Letters and Science. Located off-campus are numerous laboratories, extension centers and facilities, including the UC Davis Medical Center in Sacramento, the Lake Tahoe Center for Environmental Research, the Veterinary Medicine Teaching and Research Center in Tulare, Bodega Marine Laboratory at Bodega Bay, the College of Engineering’s applied science department at Livermore and the UC Davis Washington Center in Washington, DC. UC Davis faculty ranks 16th in quality among comprehensive public universities nationwide, according to a multi-year study of US doctoral programs reported in 1995 by the National Research Council. Creative teaching and academic innovation are encouraged by several programs, including the $30,000 Prize for Teaching and Scholarly Achievement, believed to be the largest award of its kind in the US. |
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