Correlation between viscosity and absorption of electromagnetic waves in an aqueous UNCD suspension

A model of ultrananocrystalline diamond (UNCD) particle in an aqueous suspension produced by a stirred-media milling process of detonation nanodiamonds has been suggested for the first time. This model is based on a hypothesis that surface of the single UNCD particle contains partly disconnected sp2 hybridized carbon regions. These regions are formed due to the sp3–sp2 phase transition on a surface of UNCD particle as result of local heating of that surface during the stirred-media milling process. Unusual high viscosity, UV–Vis absorption, black color in visible region of the UNCD suspension and difficulty of plasmon resonance absorption observation have been explained in the suggested model.The percolation between the sp2 regions has explained small conductivity of UNCD powder and suggests a dependence of the conductivity on conditions of the milling process.Our model fits well with recent characterization of UNCD powder by NMR and computer simulation.