The fabrication and characterization of a carbon nanotube sponge vapor sensor

• Main Authors: Hou, YU-Ling, 侯鈺玲
• Other Authors: 張士欽
• Format: Others
• Language: en_US
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/32486076974176624204

碩士 === 國立清華大學 === 材料科學工程學系 === 101 === The application of the carbon nanotube sponges made by an innovative process as organic vapor sensors was studied. Carbon nanotubes were made hydrophilic by acid treatment and then dispersed in water with PVA. After frozen, the ice in the frozen solid was removed by sublimation without melting under low pressure. Then, what left is a carbon nanotube sponge. Copper sheet electrodes were attached on the two opposite sides of the sponge to form an organic vapor sensor. The change of electric resistance of the sponge with adsorption and desorption of organic vapors were investigated. It is found that the carbon nanotube sponge sensor exhibiting high and rapid response to acetone and ethanol vapors. To shorten the recovery time of the sensor, electric current was applied to heat the CNT sensor and so increase the rate of gas desorption. When a relatively high voltage is applied, the resistance can be recovered in 5 minutes and shorten the recovery time. And then no much difference between the spectra measured before and after the test were found. In the relative humidity test, the saturated maximum resistance and the sensitivity increase linearly with increasing relative humidity from 27 % to 85 %.