Size-Dependent Reactivity of Diamond Nanoparticles

Abstract

Photonic active diamond nanoparticles attract increasing attention from a wide community for applications in drug delivery and monitoring experiments as they do not bleach or blink over extended periods of time. To be utilized, the size of these diamond nanoparticles needs to be around 4 nm. Cluster formation is therefore the major problem. In this paper we introduce a new technique to modify the surface of particles with hydrogen, which prevents cluster formation in buffer solution and which is a perfect starting condition for chemical surface modifications. By annealing aggregated nanodiamond powder in hydrogen gas, the large (>100 nm) aggregates are broken down into their core ( approximately 4 nm) particles. Dispersion of these particles into water via high power ultrasound and high speed centrifugation, results in a monodisperse nanodiamond colloid, with exceptional long time stability in a wide range of pH, and with high positive zeta potential (>60 mV). The large change in zeta potential resulting from this gas treatment demonstrates that nanodiamond particle surfaces are able to react with molecular hydrogen at relatively low temperatures, a phenomenon not witnessed with larger (20 nm) diamond particles or bulk diamond surfaces.

Communication: Three-dimensional model for phonon confinement in small particles: Quantitative bandshape analysis of size-dependent Raman spectra of nanodiamonds

“…24,25 In conclusion, we propose a physically consistent way of interpreting Raman spectra of nanoparticles. Since the 3D dispersion function takes into account the anisotropy of the phonon dispersion, the model built in this way has a straightforward physical meaning.…”

Macroscopic thermoelectric efficiency of carbon nanocomposites

“…Such diamond nanoparticles were prepared by milling [7][8][9] and before long by purification techniques [10,11] from agglomerates about 100 nm in size. Then, solid composite was produced from 4 nm particles by sintering at high pressure and high temperature (HPHT).…”

Observation of Metal Nanoparticles for Acoustic Manipulation

“…For example, it has been reported that 5 nm diamond nanoparticles could be manipulated into nodal patterns using acoustic standing waves field 24. However, driving by the high surface energy, the diamond nanoparticles with ultra‐small size are particularly known to form large agglomerates 39, 40, 41. As the nanoparticles in the experiments were not treated with a surfactant to prevent the self‐assembly, the actual manipulation effect may depend on the size of agglomerates rather than that of single nanoparticle.…”