Disposable Elastomer Ozone Detector
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Description:
The Naval Research Laboratory (NRL) has developed a fast, low-cost elastomeric ozone detector that measures the presence and concentration of ozone in ambient conditions. The device works by the formation of micron-sized surface cracks in a stretched rubber, due to reaction with ozone. This reaction causes the initially clear, transparent sample to become "frosty" (opaque). The sensitivity can be made to vary by two orders of magnitude, simply by changing the stretch of the rubber, with the ozone concentration directly related to the degree of opacity developing in the rubber. Since the "frosting" occurs only on strained samples, unstretched rubber has an indefinite shelf-life. The technology can be implemented in a variety of ways. One potential application is a "litmus paper"-type test that provides a quick "go–no go" determination. The rubber is slipped over a frame whereupon it loses its transparency at a rate dependent on the local ozone concentration. After a fixed time, the level of opacity allows quantitative determination of the ozone level. Changing the stretch of the rubber changes the sensitivity, enabling wide ranges of ozone to be detected. Short term ozone "spikes," as well as the average ozone concentration over an extended period, can be monitored. Testing can last from one minute to days. More precise evaluation of the opacity, using a photodiode, yields accurate, quantitative ozone measurements. In laboratory tests, ozone levels in air have been measured over a range from 1 to 500 ppb. Testing has shown the detection to be unaffected by the presence of other air pollutants. Sample test kits are available upon request.Advantages/Features Include:
- Economical: Sensing material is a non-toxic rubber that costs less than 10 cents per test.
- Variable sensitivity: Changing the stretch of the rubber varies sensitivity by two orders of magnitude.
- Accuracy and dynamic range: Ozone levels from 1 to 500 ppb have been measured with high accuracy and reproducibility.
Applications Include:
- Environmental monitoring
- Industrial/workplace surveillance and monitoring
- Deodorization, disinfection, and sterilization monitoring
References:
- "Elastomeric Ozone Detector," Materials Science and Engineering A317, 2001, 65.
- "Ozone Detection by Crack Induced Opacity in Rubber," Rubber Chemistry and Technology 72, 1999, 769.
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Contact:
Naval Research LaboratoryTechnology Transfer Office, Code 1004
techtran@research.nrl.navy.mil