| | Category | PH | P27 | Stability of Gold-Thiolate Nanoparticle Vapor Sensors at Elevated |
| | Temperatures |
| | Abstract | The ability to detect explosives is essential to protecting our country from |
| | terrorists. Currently, researchers are developing a micro gas |
| | chromatography system that separates and electronically identifies |
| | chemical components of a sample. Gold-thiolate nanoparticle vapor |
| | sensors, which are being tested as explosive detectors, may be used in |
| | the system. However, explosive particles are heavy and nonvolatile, so |
| | they have difficulty moving through the column. Operating the system at |
| | elevated temperatures overcomes this problem, but it may also damage the |
| | heat-sensitive sensors. The purpose of my experiment was to determine |
| | the maximum temperature that the gold-thiolate nanoparticle vapor sensors |
| | can operate at. Also, I hypothesized that crosslinking the nanoparticles |
| | reduces the sensors’ sensitivity to heat. |
| | |
| | Six gold-thiolate nanoparticles vapor sensors were constructed. They |
| | were grouped based on nanoparticle type: 4-mercapto-diphenyl-acetylene |
| | (DPA), 1-octanethiol (C8), and 1-mercapto-6-phenoxyhexane (OPH). |
| | Each type had one crosslinked and one un-crosslinked sensor. A device |
| | was engineered to measure the sensors’ resistances. Resistance |
| | measurements were taken every 60 seconds for three days at 22ºC, |
| | 50ºC, 75ºC, 90ºC, 105ºC, and 125ºC. Labview and Origin software were |
| | used to calculate each sensor’s normalized change in resistance, a |
| | standard measure of stability. |
| | |
| | The results indicate that the maximum temperature gold-thiolate |
| | nanoparticle vapor sensors can operate effectively at is 105ºC. Over |
| | 105ºC, all sensors malfunctioned (the normalized change in resistance |
| | >20%). Overall, crosslinking significantly decreased the impact of |
| | elevated temperatures on the sensors (p=0.0059). These findings are |
| | critical to the development of a micro gas chromatography system that can |
| | successfully detect explosives. |
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