Explosive sensing by using polymer tip on the end of optical fiber

The present study developed a new optical chemical sensor for detection of nitro-aromatic explosives in liquid phase. The method is based on the fluorescence quenching of conjugated polymer poly [2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV). Polymer tip on the one end of single mode optical fiber was fabricated by photo polymerization reaction method. The tip was coated with MEH-PPV and used as sensor head to detect nitro-aromatic explosives. Compared to the normal end cut fiber this kind of sensor head can gather more fluorescence signal which indicate higher sensitivity. The sensing characteristics of the tip sensor head to dinitrobenzene (DNB) which is chemically similar to the common explosive TNT was studied. The optical sensor head coated with fluorescence indicator showed strong fluorescence quenching when exposed to DNB. A Stern-Volmer graph for DNB was constructed and showed that the range of concentration from 6 mM to 30 mM was linear and the response time of the sensor was within 1 min.