Study on Measuring Particle Size Distribution of A Nanodiamond Powder

摘要

Particle size distribution (PSD) of a nanodiamond powder in a high concentration suspension was measured by a new dynamic light scattering (DLS) technique based on the Doppler frequency shifting effect. Influence of dispersing pre-treatment, distribution bases and materials' properties on DLS results was analyzed, and PSD results were validated by TEM analysis. It was found that the optimized ultrasonic dispersing time of the diamond powder in a sodium hexametaphosphate (SHP) solution was about 5 minutes. And median sizes of the nanodiamond powder were 115.6 nm, 53.0 nm and 32.6 nm, based on light intensity, volume and number respectively. PSD results of the nanodiamond based on number accorded well with results from TEM analysis. And PSD results were affected hardly by refractive indices of the diamond and the dispersing medium, while they were affected markedly by viscosity of the medium. It is concluded that this new DLS technique could measure PSD of the nanodiamond powder in high concentration suspensions which has been dispersed properly.