Water-responsive carbon nanotubes for selective detection of toxic gases

Mukherjee, Soumalya and Sakorikar, Tushar and Mukherjee, Anwesha and Misra, Abha (2015) Water-responsive carbon nanotubes for selective detection of toxic gases. In: APPLIED PHYSICS LETTERS, 106 (11).

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Abstract

Ammonia plays an important role in our daily lives and hence its quantitative and qualitative sensing has become necessary. Bulk structure of carbon nanotubes (CNTs) has been employed to detect the gas concentration of 10 ppm. Hydrophobic CNTs were turned to hydrophilic via the application of a ramp electric field that allowed confinement of a controlled amount of water inside CNT microstructure. These samples were then also used to detect different gases. A comparative study has been performed for sensing three reducing gases, namely, ammonia, sulphur-di-oxide, and hydrogen sulphide to elaborate the selectivity of the sensor. A considerable structural bending in the bulk CNT was observed on evaporation of the confined water, which can be accounted to the zipping of individual nanotubes. However, the rate of the stress induced on these bulk microstructures increased on the exposure of ammonia due to the change in the surface tension of the confined solvent. A prototype of an alarm system has been developed to illustrate sensing concept, wherein the generated stress in the bulk CNT induces a reversible loss in electrical contact that changes the equivalent resistance of the electrical circuit upon exposure to the gas. (C) 2015 AIP Publishing LLC.

Item Type:	Journal Article
Publication:	APPLIED PHYSICS LETTERS
Publisher:	AMER INST PHYSICS
Additional Information:	Copy right for this article belongs to the AMER INST PHYSICS, 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA
Keywords:	AMMONIA SENSOR; SURFACE; NANOPARTICLES; TRANSITION; TRANSPORT; BEHAVIOR
Department/Centre:	Division of Physical & Mathematical Sciences > Instrumentation Appiled Physics
Date Deposited:	24 Apr 2015 05:30
Last Modified:	24 Apr 2015 05:30
URI:	http://eprints.iisc.ac.in/id/eprint/51366

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