scispace - formally typeset
Search or ask a question
Topic

Vapours

About: Vapours is a research topic. Over the lifetime, 1153 publications have been published within this topic receiving 15022 citations.


Papers
More filters
Journal ArticleDOI
TL;DR: In this paper, thin films of titanium dioxide (TiO 2 ) powder, dispersed in polyvinylidenfluoride and deposited on glass slides containing gold electrodes, are used as sensors for benzene, ethanol and methanol vapours at room temperature.
Abstract: Thin films of titanium dioxide (TiO 2 ) powder, dispersed in poly(vinylidenfluoride) and deposited on glass slides containing gold electrodes, are used as sensors for benzene, ethanol and methanol vapours at room temperature. The resistance of the films at a potential difference of 1.5 V is determined when the films are exposed to atmospheres containing these vapours with concentrations over the range 150–350 ppm. The relative resistance, Δ R , of the films increases linearly with increasing concentrations of the vapours (regression coefficients, r =0.90, 0.98 and 0.97 for benzene, methanol and ethanol, respectively). The findings are consistent with the TiO 2 films having p-type semiconductor characteristics. The responses of the films are reversible with changes in Δ R of 0.042, 0.1 and 0.122% ppm −1 for benzene, ethanol and methanol, respectively. The response times to increasing concentrations of the vapours are about 1, 2 and 2 min for benzene, ethanol and methanol, respectively, and the corresponding values for decreasing concentrations 5, 6 and 6 min, respectively. The limit of detection for the vapours is about 10 ppm. With improvements in the sensitivity, selectivity and stability, the films could form the basis of a handheld instrument for the atmospheric monitoring of benzene.

107 citations

Journal ArticleDOI
01 Jan 1992-Analyst
TL;DR: The response mechanism of poly(pyrrole) to a selection of gases and vapours was investigated using two techniques: measurement of resistance change and mass changes using a piezoelectric quartz crystal microbalance with the objective of characterizing responses for incorporation in sensor arrays as discussed by the authors.
Abstract: The response mechanism of the conducting polymer poly(pyrrole) to a selection of gases and vapours was investigated using two techniques: measurement of resistance change and mass changes using a piezoelectric quartz crystal microbalance with the objective of characterizing responses for incorporation in sensor arrays. Bromide-doped films were exposed to methanol, hexane, 2-2-dimethylbutane, ammonia and hydrogen sulfide. Polymers of different thicknesses were also exposed to methanol vapour and the response profiles were studied. The responses were all of a Fickian type except the piezoelectric signal, which exhibited an anomalous non-Fickian response to methanol. This suggests that the poly(pyrrole) resistance changes frequently observed are partly due to one stage in the two-stage sorption perhaps involving the swelling of the polymer. It was concluded that the response mechanism of poly(pyrrole) sensing of different gases and vapours is due to a mixed response involving electronic effects and physical effects.

104 citations

Journal ArticleDOI
TL;DR: In this paper, a new technique for the deposition of free-standing porous silicon (PS) on alumina substrate with interdigital contacts was developed, thus removing the silicon substrate, that is inactive in gas detection and is much more conductive than PS.
Abstract: We developed a new technique for the deposition of free-standing porous silicon (PS) on alumina substrate with interdigital contacts (Italian Patent ENEA-INFM), thus removing the silicon substrate, that is inactive in gas detection and is much more conductive than PS. The dc and ac electrical measurements in a controlled atmosphere were performed to test the sensor response towards NO 2 (0.1–10 ppm), O 3 (200 ppb), CO (1000 ppm), benzene (20 ppm), organic vapours and humidity. The device was able to detect very low concentrations of nitrogen dioxide (100 ppb) with no interference from ozone, benzene, CO and organic vapours. Indeed humidity interferes with nitrogen dioxide detection and must be kept under control. Since PS showed great response to NO 2 at room temperature (RT), no heating of the sensor is required.

102 citations


Network Information
Related Topics (5)
Aqueous solution
189.5K papers, 3.4M citations
76% related
Electrolyte
124.6K papers, 2.3M citations
76% related
Adsorption
226.4K papers, 5.9M citations
75% related
Hydrogen
132.2K papers, 2.5M citations
75% related
Nanoparticle
85.9K papers, 2.6M citations
73% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202337
202276
202112
202025
201914
201818