Preparation of honeycomb films from nitryl poly(ether ether ketone)s via water-droplet templating

The fabrication of honeycomb-patterned films from nitryl poly(ether ether ketone)s (PEEK-NO2) in a high-humidity atmosphere was reported in this article. PEEK-NO₂ was prepared through acid (nitric acid and sulfuric acid) nitration from poly(ether ether ketone)s (PEEK). The obtained polymer, which was characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC) showed excellent solubility and thermal stability. Some influence factors on the pattern formation and the fabrication of the porous structure, such as the solution concentration, the solvent, and the atmosphere humidity, were investigated. The results showed that with the increase of the solution concentration, the aperture of the film diminished gradually; the lower the solventŚ boiling point were, the smaller the filmŚ apertures were and the more regular the poreŚ arrange ; only under high-humidity circumstances could obvious and ordered honeycomb films be formed.