Crystallinity and surface electrostatics of diamond nanocrystals

Colloidal diamond nanoparticles are currently among the most synthesized nanomaterials on the market, and new emerging applications for nanodiamonds include bio-nano and polymer-based composites. The reliability and reproducibility of these composite materials will be strongly linked to the size, shape and stability of the individual nanodiamonds, which has an important impact on the strength and uniformity of the bonding between the particles and the polymers or bio-molecules. Although some attention has been given previously to the structure of nanodiamond surfaces, little attention has been given to the electrostatic potential at the surface, or to the structure of the cores. In the present study we use density functional tight binding to systematically examine the core structure of diamond nanoparticles of various shapes between similar to 1-3.3 nm in diameter. In addition to this, we present results of the surface electrostatic potential that indicate a preferred orientation for particle-particle interactions in agglomerates, and the assembly of nanodiamond with polymers or bio-molecules.