In a significant breakthrough that will enable detection of explosives without destroying them, Indian scientists have developed a layer by layer (LBL) polymer detector for the purpose.

The LBL has been the brainchild of a team of scientists led by Dr Neelotpal Sen Sarma from the Institute of Advanced Study in Science and Technology, Guwahati, an autonomous institute of the Department of Science & Technology under the Central government.

The thermally stable and cost-effective electronic polymer-based sensor will help in the rapid detection of nitro-aromatic chemicals used in high-energy explosives.

The discovery assumes significance as detection of explosives without destroying them is essential for protection, and criminal investigations, minefield remediation, military applications, ammunition remediation sites and security applications. Chemical sensors play a vital role in such cases, according to a ministry of science and technology note here.

With the development of such an explosive detection system, the detection on the basis of conducting property will help in making a handy detection device where results can be seen with the help of a LED.

Though explosive poly-nitroaromatic compounds can be analyzed usually by sophisticated instrumental techniques, the requirements for quick decision making in criminology laboratories or reclaimed military sites or to detect explosives in possession of extremists often require simple, cheap, and selective field techniques which will be 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 conducting property has not been explored so far, the Science and Technology ministry note said.

Dr Neelotpal Sen Sarma speaking about his discovery said, “An electronic sensing device built around a polymer gas sensor can quickly detect the explosive on-site.” The device can be operated at room temperature. It has a low response time and negligible interference from other chemicals. The fabrication is very simple. The effect of humidity on the device is negligible. Besides the cholesterol-based polymers used in the device are also biodegradable, he said.