Diphenylacetylene Polymer Nanofiber Mats Fabricated by Freeze Drying: Preparation and Application for Explosive Sensors

Finely structured diphenylacetylene polymer nanofibers were successfully prepared by a freeze drying method. SEM revealed that the morphology and structure of the fibers were significantly dependent on the concentration of the polymer solution, the ‘frozen in’ quenching temperature and the chemical structure of the polymer derivatives. Polarized fluorescence spectroscopy revealed that the polymer chains within the nanofiber were uniaxially oriented and highly elongated. The polymer nanofiber was remarkably sensitive to explosive nitroaromatic compounds when compared to the corresponding thin films. The fluorescence of polymer nanofiber obtained from 0.003 wt.‐% cryogenic benzene solution rapidly decreased to 50% of its initial value in ≈35 s by exposing to 2,4‐dinitrotoluene. Finely structured, fluorescent polymer nanofibers are obtained from the freeze drying of a diphenylacetylene polymer in dilute solution, which show a remarkably rapid fluorescence quenching upon exposure to explosive nitroaromatic compounds such as 2,4‐dinitrotoluene, compared to the corresponding thin films.