Abstract: The present invention provides a dispersion composition in which a nanocarbon material having a graphene structure is dispersed at nano-scale in a dispersion medium. The present invention also provides a nanocarbon material which has a graphene structure and has excellent dispersibility in a dispersion medium. A nanocarbon material dispersion composition includes a dispersion medium and the nanocarbon material dispersed at nano-scale in the dispersion medium, the nanocarbon material including a nanodiamond particle and a graphene layer formed on the surface of the nanodiamond particle, and the nanocarbon material has: a wavenumber, which corresponds to a peak-top value in a wavenumber range of 1580±50 cm?1 in a Raman spectrum, from 1585 cm?1 to 1630 cm?1; and a peak that appears at 2?=43 to 44° in an XRD analysis.

Abstract: Provided is a method for producing a surface-modified nanodiamond having its surface modified with a group containing a polyglycerin chain in an industrially efficient and safe manner, the surface-modified nanodiamond having excellent solubility or dispersibility in water and a polar organic solvent and great dispersion stability. In an aliphatic alcohol solvent having from 2 to 4 carbon atoms, a nanodiamond or a surface-modified nanodiamond having its surface modified with a group represented by Formula (1): —X1—H (1), where in Formula (1), X1 represents —NH—, —O—, —COO—, or the like, is subjected to ring-opening addition polymerization with glycidol, so as to obtain a surface-modified nanodiamond having its surface modified with a group containing a polyglycerin chain represented by Formula (2): —X—R (2), where in Formula (2), X represents a single bond, —NH—, —O—, —COO—, or the like, and R represents a polyglyceryl group.