Plasma treatment of detonation and HPHT nanodiamonds in diffuse coplanar surface barrier discharge in H2/N2 flow.

Due to extraordinary properties and biocompatibility, diamond nanoparticles - nanodiamonds (NDs) are considered for various biomedical applications. Amongst other functional groups which may be grafted on the NDs surface, the amines (NH _x) are highly demanded linkers for biomolecules and dyes. In this regard, a non-destructive, non-hazardous and low-cost method of NDs amination would further accelerate their industrial applications in biomedicine and life science. Here we present a study on NDs treatment using diffuse coplanar surface barrier discharge in the gas mixture H₂:N₂ = 1:1 at the atmospheric pressure. Detonation and high pressure-high temperature nanoparticles (D-NDs and HPHT-NDs) were used either as-received or air-annealed. The FTIR spectra confirmed the presence of N-H stretching vibrations for all kinds of NDs after the treatment. It was revealed by XPS and FTIR measurements that both kinds of D-NDs (as-received and air-annealed) exhibited higher content of −NH₂ functions in the detected nitrogen groups than HPHT-NDs. The treatment of as-received D-NDs led to the conversion of −COOH groups to amides. A large increase of C-H bonds after the discharge treatment was found, especially for the annealed NDs forms. Raman spectroscopy revealed a decrease of sp² carbon after the treatment of the as-received HPHT-NDs. [ABSTRACT FROM AUTHOR]