Resorcinarene amine stabilized nanodiamond dispersions in organic solvents: applications in diamond film growth

Abstract

Nanodiamonds of widely differing sizes (4 to >100 nm), shapes, and origin could be extracted from aqueous dispersions into toluene by a multidentate resorcinarene amine surfactant, in the absence of any elaborate covalent functionalization or extreme conditions. Resorcinarene amine encapsulated nanodiamonds displayed excellent dispersion stability in non-polar organic solvents for several months. The IR spectral analysis of these extracted and further precipitated nanodiamonds suggests that the carboxylic acid groups present on the nanodiamond surfaces are electrostatically stabilized by the resorcinarene amine surfactant. Such nanodiamond dispersions can also act as nucleation sources for the fabrication of continuous diamond films by CVD growth. Notably, this process resulted in diamond films with better uniformity, smaller grain size and reduced surface roughness when compared to the films prepared with unmodified nanodiamonds as nucleating agents.