Evaluation of dispersion and aggregation of nanoparticles in liquid metal via NMR

Tei, C.  ; Otaka, Masahiko; Kuwahara, Daisuke*

Evaluation of nanoparticles in liquid phase dispersants has been carried out by using methods such as particle size measurement and transmission electron microscopy. It is difficult to apply it to chemically active liquid metals (impermeable to visible light) that cannot be handled in the atmosphere. In this study, the NMR methods based on evaluating the interfacial state of sodium-nanoparticles in liquid metallic sodium (Na) was investigated for metallic nanoparticle dispersions. There are two types liquid Na in contact with the surface of the nanoparticles (atomic state bound to the particle surface) and liquid Na away from the particle surface (free atomic state). The relaxation time of each depends on the bound state of the atoms. The clear difference in relaxation times and the relative specific surface area estimated from the relaxation times are also obtained, leading to the development of methods for assessing the state of nanoparticles in liquid metal.