摘要： Organo-nanodiamond (ND) by surface modification using several surfactants has achieved nanodispersion in organic solvent as if these nanoparticles were dissolved. High surface coverage has reduced the aggregated particle size of organo-ND particles in the solvent, and their modification by fluorocarbon chain has achieved nanodispersion in a nonpolar solvent. By using a spreading solvent for single particle layers on the water surface of various organo-NDs of resulting dispersion medium, a close relation was found between the dispersion characteristics of organo-nanoparticles in the solvent and the condensation behavior in their two-dimensional single particle layer. Organo-ND with high dispersion ability in solvent has inferior two-dimensional condensability as a single particle layer. Sufficient retention time is necessary to form a homogeneous single particle layer on the water surface. The reason behind this property was found to be the secondary aggregation of organo-modified nanoparticles at the air/water interface. Since lipophilicized ND is not necessarily stable on the water surface, increasing aggregated particle size and three-dimensionality were confirmed in the case where the particle compression rate during two-dimensional integration was relatively fast.