Abstract: A nanodiamond particle dispersion including nanodiamond particles highly dispersed in an organic solvent is provided. A nanodiamond particle dispersion of the present invention includes nanodiamond particles dispersed in an organic solvent, in which the nanodiamond particles have a silane compound (excluding a silane compound having a (meth)acryloyl group) bonded to a surface of the nanodiamond particles, the organic solvent has an SP value from 8.0 to 14.0 (cal/cm3)1/2, and the nanodiamond particles are dispersed with a particle diameter (D50) from 2 to 100 nm. The organic solvent is preferably at least one type of organic solvent selected from ketones, ethers, alcohols, and carbonates.

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.

Abstract: A nanodiamond particle dispersion including nanodiamond particles highly dispersed in an organic solvent is provided. A nanodiamond particle dispersion of the present invention includes nanodiamond particles dispersed in an organic solvent, in which the nanodiamond particles have a silane compound (excluding a silane compound having a (meth)acryloyl group) bonded to a surface of the nanodiamond particles, the organic solvent has an SP value from 8.0 to 14.0 (cal/cm3)1/2, and the nanodiamond particles are dispersed with a particle diameter (D50) from 2 to 100 nm. The organic solvent is preferably at least one type of organic solvent selected from ketones, ethers, alcohols, and carbonates.