Evidence for plasma synthesis of an amorphous polynitrogen on carbon nanotubes

Radio-frequency plasma synthesis of polynitrogen (PN) stabilized on single- and multiwall carbon nanotubes has been carried out using nitrogen mixed with argon or with hydrogen as precursors. Characterization of the samples produced was conducted by Raman spectroscopy (Raman), attenuated total reflectance-Fourier transform infrared spectroscopy, scanning (SEM) and transmission (TEM) electron microscopy, energy-dispersive x-ray spectroscopy, x-ray photoelectron spectroscopy, and differential scanning calorimetry (DSC). Raman, SEM, and TEM showed that an amorphous PN phase is formed on the sidewalls and inside the carbon nanotubes (CNTs), which decomposes exothermally at approximately 300◦C, as indicated by DSC measurements. Molecular modeling assessment of the energy performance was carried out for the related nitrogen chain N₈ molecule hosted inside a CNT and combined with the double-base energetic material (nitrocellulose, nitroglycerin). Similar assessment was also carried out for a promising nitrogen-rich molecule, 3,6-di(hydrazino)-1,2,4,5-tetrazine (DHT), in its double-base form. The encapsulation of this system inside a nitrogendoped CNT was considered for showing the effect of CNTs on energetic performance.