Indian scientists develop cost-effective device to rapidly detect explosives

Vijay Mohan

Tribune News Service

Chandigarh, September 24

Indian scientists have developed a thermally stable and cost-effective electronic polymer-based sensor for rapidly detecting nitro-aromatic chemicals used in high-energy explosives.

The detection of explosives without destroying them is essential for protection, and criminal investigations, minefield remediation, military applications, ammunition remediation sites, security applications. Chemical sensors play a vital role in such cases.

Though explosive poly-nitroaromatic compounds can usually be analysed by sophisticated instrumental techniques, the requirement for quick decision-making in criminology laboratories, reclaimed military sites or to detect explosives in possession of extremists often require simple and cheap field techniques which are non-destructive in nature.

Non-destructive sensing of nitroaromatic chemicals (NACs) is difficult. While earlier studies are based mostly on photo-luminescent property, detection of the basis of a material’s conducting property has not been explored so far. Detection on the basis of conducting property helps in making a handy detection device where results can be seen with the help of a LED.

To overcome such disadvantages, a team of scientists led by Dr Neelotpal Sen Sarma from the Institute of Advanced Study in Science and Technology, an autonomous institute of the Department of Science and Technology, has developed an electronic layer-by-layer (LBL) polymer detector consisting of two organic polymers, which undergoes a drastic change in impedance in the presence of very low concentration of NACs vapour within few seconds. “An electronic sensing device build around a polymer gas sensor can quickly detect the explosive on-site,” said Dr Sarma.

The tri-layer polymer matrix was found to be very efficient molecular sensor for nitroaromatic chemicals. The sensor device is quite simple and reversible in nature and its response does not alter with varying operating temperature in presence of other common chemicals and humidity.

The device can be operated at room temperature, has a low response time and negligible interference from other chemicals. The fabrication is a very simple, is negligibly affected by humidity, and the cholesterol-based polymers used are biodegradable.