Molecular recognition and self-assembled polymer films for vapor phase detection of explosives

Selective and sensitive polymer films for detecting explosives were studied and fabricated onto surface acoustic wave (SAW) devices. Polymers and molecular host species were self-assembled on functionalized silicon oxide surfaces through a catalytic hydrosilylation reaction. The covalently attached thin polymer films are stable, continuous and uniform with film thickness ranging from 15 to 30 nm. The microsensors coated with the polymer films show high sensitivity towards 2,4-dinitrotoluene (DNT) and o-nitrotoluene, an explosive simulant. Sensor responses to possible common interferents in land mine detection were studied and the sensor sensitivities to them were found to be much lower than that to DNT and explosives simulants. Response patterns for interferants and o-nitrotoluene were constructed and the sensors coated with functionalized cyclodextrins were able to detect 2,4-DNT and 2,4,6-trinitrotoluene (TNT) under ambient laboratory conditions.