Nitroaromatic explosive sorption and sensing using electrochemically processed polyaniline-titanium dioxide hybrid nanocomposite

• Titanium oxide nanotube/polyaniline hybrid composites were made.
• Explosive sorption tests were conducted.
• Nanostructured titanium oxide nanotube sorbs more TNT than pure titanium.
• Polyaniline coated titanium dioxide nanotube changes color after it sorbs TNT.
• Nanotubes coated with polyaniline show UV responses in TNT solutions.

This work deals with synthesis and characterization of polyaniline and titanium dioxide nanocomposites for explosive detection and mitigation. The titanium dioxide nanotube array was prepared through electrochemical oxidation of pure titanium in a fluorine ion-containing ethylene glycol water solution followed by annealing at 450 °C in air. Polyaniline was obtained by electrochemical polymerization from an aniline and sulfuric acid solution. Both polyaniline and the nanotube show sorption of 2,4,6-trinitrotoluene (TNT) vapor at 60 °C. Polyaniline modified by alginic acid sodium salt caused color change of TNT solutions. Polyaniline-based sensor showed decrease of electrical resistance in TNT acetonitrile solutions. Ultraviolet light response tests revealed that TNT caused significant drop in open circuit voltage of the titanium dioxide nanotube. In addition, the polyaniline/titanium oxide nanocomposites show colorimetric responses in the explosive solution, which makes them have multiple response mechanisms for nitro-aromatic explosive detection and mitigation.

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