Chapter 10 - Detection of Explosives Using Amplified Fluorescent Polymers

Over the past two decades, organic conjugated polymers have emerged as an attractive alternative to inorganic-based materials in numerous electronics and optoelectronics applications. Amongst these, there has been intensive research in conjugated polymers for electrochromic (EC) applications. EC materials are materials that exhibit a change in color upon oxidation and/or reduction due to the application of external electrical potential bias. Such materials have been found useful in smart windows, smart glasses and mirrors, as well as military camouflage paint. Compared with traditional metal oxide-based EC materials, conjugated polymer-based EC materials offer the advantages of color variety, lightweightness, flexibility, solution processability, low cost and low toxicity. To date, numerous EC conjugated polymers have been reported with a color range spanning across the entire visible region, even extending to the infrared region. In this chapter, we will start with a brief introduction to the fundamentals of conjugated polymers, electrochromism and EC devices. Then, we will summarize various types of conjugated polymers for EC applications. Finally, the challenges and perspectives that we face in the EC area will be commented.

Molecular modeling techniques were employed to study the interaction of trinitrotoluene with an amplifying fluorescent polymer used in explosive sensor devices. The pentiptycene moiety present in these polymers appears to be the most energetically favorable binding site for trinitrotoluene. Surface features of the polymer suggest that the small cavity feature of the pentiptycene moiety may be more available for binding to analyte compounds due to steric crowding about the large cavity. Binding energies between model binding sites of the polymer and various analyte compounds were more rigorously estimated by semiempirical and ab initio techniques. Binding energies were found to be largest with trinitrotoluene and other nitroaromatic compounds. Electrostatic and π-stacking interactions between trinitrotoluene and the model host were investigated by studying a series of modified host compounds.