Surface-modified nanodiamond, liquid dispersion including surface-modified nanodiamond, and resin dispersion
The present invention is to provide a surface-modified nanodiamond having excellent affinity for an organic solvent and a resin and having high dispersibility in an organic solvent and in a resin. 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 Formula (1), R 1 represents an aliphatic hydrocarbon group having 6 or more carbons. R 2 and R 3 may be the same or different and are each a hydrogen atom, an aliphatic hydrocarbon group having from 1 to 3 carbons, or a group represented by Formula (2) below.
1. A nanodiamond liquid dispersion comprising:
a surface-modified nanodiamond in a concentration of 0.0001 to 10 mass %; and
an organic solvent in a content of 90 mass % or greater,
the surface-modified nanodiamond and the organic solvent being present in a total content of 95 mass % or greater,
wherein the surface-modified nanodiamond have a structure in which a surface of a nanodiamond particle is modified by a group represented by Formula (1):
where R 1 represents an aliphatic hydrocarbon group having 6 or more carbons, an atomic bond indicated by a wavy line bonds to the surface of the nanodiamond particle, and R 2 and R 3 may be the same or different and are each a hydrogen atom, an aliphatic hydrocarbon group having from 1 to 3 carbons, or a group represented by Formula (2):
where R 1 is as described above, R 5 and R 6 may be the same or different and each represent a hydrogen atom or an aliphatic hydrocarbon group having from 1 to 3 carbons, m and n may be the same or different and each represent an integer of 0 or greater, an atomic bond extending toward left from a silicon atom bonds to an oxygen atom, and an atomic bond indicated by a wavy line bonds to the surface of the nanodiamond particle.
2. The nanodiamond liquid dispersion according to claim 1 , wherein the organic solvent is an aromatic hydrocarbon.
3. The nanodiamond liquid dispersion according to claim 1 , wherein a median diameter of the surface-modified nanodiamond included in the organic solvent is 100 nm or less.
4. The nanodiamond liquid dispersion according to claim 1 , wherein the nanodiamond liquid dispersion has properties below:
in a case where a liquid component is removed from the nanodiamond liquid dispersion to produce a powdered surface-modified nanodiamond and the powdered surface-modified nanodiamond is redispersed in the organic solvent to prepare a nanodiamond liquid dispersion having a solid content concentration of 1 wt. %, a particle diameter (D50) of the surface-modified nanodiamond in the prepared nanodiamond liquid dispersion is from 10 to 100 nm.
5. The nanodiamond liquid dispersion according to claim 2 , wherein a median diameter of the surface-modified nanodiamond included in the organic solvent is 100 nm or less.
6. A nanodiamond liquid dispersion according to claim 1 , wherein R 1 in formula (1) is an alkyl group having from 14 to 25 carbons.
7. The nanodiamond liquid dispersion according to claim 6 , wherein a median diameter of the surface-modified nanodiamond included in the organic solvent is 100 nm or less.
8. The nanodiamond liquid dispersion according to claim 6 , wherein a concentration of the surface-modified nanodiamond is from 0.0001 to 10 mass %.
9. The nanodiamond liquid dispersion according to claim 6 , wherein the nanodiamond liquid dispersion has properties below:
in a case where a liquid component is removed from the nanodiamond liquid dispersion to produce a powdered surface-modified nanodiamond and the powdered surface-modified nanodiamond is redispersed in the organic solvent to prepare a nanodiamond liquid dispersion having a solid content concentration of 1 wt. %, a particle diameter (D50) of the surface-modified nanodiamond in the prepared nanodiamond liquid dispersion is from 10 to 100 nm.