doi:10.1038/nindia.2011.112 Published online 26 July 2011
Researchers have designed a novel sensor to detect cigarette smoke using a nanosized conducting polymer coated with nickel nanoparticles. The sensor could be used to detect cigarette smoke in 'no smoking' zones.
Conducting polymer is an emerging nanomaterial with potential applications in optical and microelectronic devices, chemical sensors, catalyzers, drug delivery, and energy storage systems. They are also effective as gas sensors. However, no study has explored the potential of polymer wires in sensing cigarette smoke.
The researchers used camphor sulphonic acid (CSA) as doping agent to produce nickel nanoparticle-coated one dimensional polyaniline nanowire (PANI-CSA-Ni) and compared it with a bare nanowire (PANI-CSA). The sensor was made by placing the Ni-coated and bare nanowires between two perforated copper plates.
The sensor was placed in a closed chamber with an inlet for cigarette smoke to study the resistance of both nanowires in response to current signal at different frequencies. The Ni-coated nanowire took around two minutes to sense cigarette smoke. The resistance response of bare nanowire was less drastic.
Nickel is known to form a complex with nicotinic acid and furan present in cigarette smoke. Formation of Ni complex on the surface of nanowire generated mobile charge carriers. This enhanced the conductivity of the Ni-coated nanowire bringing down its resistance value by four orders.
"With smoking banned in public places in India, the cigarette smoke detector will be a helpful tool for enforcement agencies," says lead researcher Devasish Chowdhury.