Sniffer polymers hunt out explosives

A team of US researchers has found a way to sniff out plastic explosives using polymer-based devices.  

Current security methods to detect explosive materials rely on the acute senses of trained dogs. Now Timothy Swager and colleagues at the Massachusetts Institute of Technology have developed the devices using amplifying fluorescent polymers that are known to detect the vapours of some high explosives such as 2,4,6-trinitrotoluene (TNT). 

To compete with the standards attained by sniffer dogs, these polymer-based devices must be able to sense all types of explosives. Plastic explosives are particularly hard to detect because they have very low vapour pressures. However, Swager found that the taggant molecule, 2,3-dimethyl-2,3-dinitrobutane (DMNB), which must legally be added to manufactured plastic explosives, can be detected using the devices. 

The additive DMNB proved a difficult molecule for the researchers to detect because the structure is highly three-dimensional and intermolecular binding between the analyte and the film is weak.  

Swager and his team took into account the factors that are crucial to detecting vapour phase analytes before testing a range of conjugated polymers.  

’The highly sensitive detection which this technology offers of a higher vapour pressure taggant already present in legally manufactured explosives could potentially lead to a screening platform for stolen plastic explosives,’ said Swager. 

Alison Stoddart