Abstract: Provided are: a polyglycerin-chain surface-modified nanodiamond having excellent dispersibility in a low-polarity solvent; and a method of producing the polyglycerin-chain surface-modified nanodiamond. A surface-modified nanodiamond 1 includes a nanodiamond particle 2 and a surface-modifying group 3 that surface-modifies the nanodiamond particle 2, the surface-modifying group 3 having a polyglycerin chain in which a hydrogen atom of at least some of the hydroxyl groups in the polyglycerin chain is substituted by a monovalent organic group.

Abstract: Provided is a composition for a refrigeration machine capable of reducing a friction coefficient in friction between sliding members in a refrigeration machine, and a composition kit for a refrigeration machine for providing the composition for a refrigeration machine. A composition for a refrigeration machine of the present disclosure includes a refrigeration machine oil, nanodiamond particles dispersed in the refrigeration machine oil, and a dispersant. The refrigeration machine oil preferably contains a polyvinyl ether, a polyol ester, a polyalkylene glycol, an alkylbenzene, or a mineral oil. The composition kit for a refrigeration machine of the present disclosure includes a refrigeration machine oil (A) containing a base oil and nanodiamond particles dispersed in the base oil, and a refrigerant (B).

Abstract: Provided is a polyoxyalkylene-chain surface-modified nanodiamond that is excellent in safety during production and in productivity. A surface-modified nanodiamond according to the present invention includes a nanodiamond particle and a surface-modifying group having a polyoxyalkylene chain and a silicon atom, the surface-modifying group surface-modifying the nanodiamond particle. A nanodiamond dispersion composition according to the present invention includes a dispersion medium and the surface-modified nanodiamond dispersed in the dispersion medium.

Abstract: Provided is a surface-modified nanodiamond that has high dispersibility in an organic solvent or in a resin and that can maintain the characteristics described above even in a high-temperature environment of 200° C. or higher. The surface-modified nanodiamond according to an embodiment of the present invention has a structure in which a surface of a nanodiamond particle is modified by a group represented by Formula (1) below. In the formula, R1 to R4 are the same or different and each represent an aliphatic hydrocarbon group having from 1 to 25 carbons. Note that at least one of R1 to R4 is an aliphatic hydrocarbon group having from 10 to 25 carbons. Furthermore, an atomic bond of the carbon atom in the formula bonds to the surface of the nanodiamond particle.

Abstract: Provided is a composition for a refrigeration machine capable of reducing a friction coefficient in friction between sliding members in a refrigeration machine, and a composition kit for a refrigeration machine for providing the composition for a refrigeration machine. A composition for a refrigeration machine of the present disclosure includes a refrigeration machine oil, nanodiamond particles dispersed in the refrigeration machine oil, and a dispersant. The refrigeration machine oil preferably contains a polyvinyl ether, a polyol ester, a polyalkylene glycol, an alkylbenzene, or a mineral oil. The composition kit for a refrigeration machine of the present disclosure includes a refrigeration machine oil (A) containing a base oil and nanodiamond particles dispersed in the base oil, and a refrigerant (B).

Abstract: Provided is a battery electrolytic solution in which a nanocarbon material is highly dispersed. The battery electrolytic solution contains: a dispersion medium; an electrolyte dissolved in the dispersion medium; and a nanocarbon material dispersed with an average dispersed particle size of 500 nm or less in the dispersion medium. The battery electrolytic solution preferably contains the nanocarbon material in an amount from 10 to 100000 mass ppm. The nanocarbon material is preferably at least one selected from the group consisting of a nanodiamond, a fullerene, a graphene, a graphene oxide, a nanographite, a carbon nanotube, a carbon nanofilament, an onion-like carbon, a diamond-like carbon, an amorphous carbon, a carbon black, a carbon nanohorn, and a carbon nanocoil.

Abstract: Provided are: a polyglycerin-chain surface-modified nanodiamond having excellent dispersibility in a low-polarity solvent; and a method of producing the polyglycerin-chain surface-modified nanodiamond. A surface-modified nanodiamond 1 includes a nanodiamond particle 2 and a surface-modifying group 3 that surface-modifies the nanodiamond particle 2, the surface-modifying group 3 having a polyglycerin chain in which a hydrogen atom of at least some of the hydroxyl groups in the polyglycerin chain is substituted by a monovalent organic group.

Abstract: Provided is a polyoxyalkylene-chain surface-modified nanodiamond that is excellent in safety during production and in productivity. A surface-modified nanodiamond according to the present invention includes a nanodiamond particle and a surface-modifying group having a polyoxyalkylene chain and a silicon atom, the surface-modifying group surface-modifying the nanodiamond particle. A nanodiamond dispersion composition according to the present invention includes a dispersion medium and the surface-modified nanodiamond dispersed in the dispersion medium.

Abstract: Provided is a surface-modified nanodiamond that has high dispersibility in an organic solvent or in a resin and that can maintain the characteristics described above even in a high-temperature environment of 200° C. or higher. The surface-modified nanodiamond according to an embodiment of the present invention has a structure in which a surface of a nanodiamond particle is modified by a group represented by Formula (1) below. In the formula, R1 to R4 are the same or different and each represent an aliphatic hydrocarbon group having from 1 to 25 carbons. Note that at least one of R1 to R4 is an aliphatic hydrocarbon group having from 10 to 25 carbons. Furthermore, an atomic bond of the carbon atom in the formula bonds to the surface of the nanodiamond particle.